Celestial Calendar


Va invitam ca la planificare  observatiilor voastre astronomice  sa folositi  ''Celestial Calendar /Calendarul celest'' pus la dispozitia comunitatii internationale de astronomi amatori de catre reputatul Dave Mitsky.
Momentele evenimentelor sunt date in Timp Universal,simbolizat cu UT.
Pentru a obtine momentele evenimentelor in ''ora de vara'' pentru Romania ,prescuratata ODV ,adaugati trei ore la ora in Timpul Universal UT.
Inafara de precizarea cronologica a evenimentelor astronomice si a momentelor acestora , acest calendar contine date  relevante pentru luna in curs din Istoria Astronomiei precum si o bogata colectie de trimiteri la resurse de informatii detaliate de pe Internet , pentru fiecare categorie de obiecte ceresti.
Multumim d-lui Dave Mitsky pentru permisiunea acordata si-i uram sanatate si succes deplin pe mai departe!
Daca pe parcursul lunii va avea loc vreo actualizare a calendarului , acesta va fi republicat aici in noua varianta revizuita.
Thank you for the permission ,we are very grateful , all the best to Dave Mitsky !

February Celestial Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract five hours and, when appropriate, one calendar day for EST)

2/1   The Moon is 4.2 degrees southeast of Uranus at 7:00; the Lunar X (the Purbach or Werner Cross), an X-shaped clair-obscure illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to be fully formed at 10:32; Mars is at the descending node through the ecliptic plane at 18:00
2/2   The astronomical cross-quarter day (i.e., a day half way between a solstice and an equinox) known as Imbolc, Candlemas, or Groundhog Day occurs today; First Quarter Moon occurs at 1:42; asteroid 4 Vesta is 0.5 degree south of the Moon, with an occultation occurring in western Canada, Alaska, eastern Russia, Japan, China, the northern Philippines, southern Asia, and eastern Afghanistan, at 9:00
2/3   The Moon is 7.2 degrees southeast of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 14:00
2/4   The Moon is 3.0 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 7:00
2/5   The Moon is 1.4 degrees south of the bright open cluster M35 in Gemini at 23:00
2/7   The Moon is 8.9 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 9:00; the Moon is 5.3 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 13:00; Mercury is at the ascending node through the ecliptic plane at 13:00
2/8   The Moon is 1.3 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 12:00
2/9   Full Moon (known as the Hunger, Snow, or Storm Moon) occurs at 7:33
2/10 The Moon is 3.6 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 0:00; Mercury is at greatest eastern elongation (18.2 degrees) at 14:00; the Moon is at perigee, subtending 33' 09" from a distance of 360,461 kilometers (223,980 miles), at 20:28
2/11 The equation of time, the difference between mean solar time (as indicated by clocks) and apparent solar time (as indicated by sundials), is at a minimum of -14.24 minutes at 22:00
2/12 Mercury is at perihelion (0.3075 astronomical units from the Sun) at 5:00
2/13 Saturn is at the descending node through the ecliptic plane at 3:00; asteroid 4 Vesta is stationary at 7:00; the Moon is 0.6 degree north of the asteroid 4 Vesta, with an occultation occurring in northern South America, the Caribbean, Central America, and North America with the exception of northeast Canada, at 10:00; the Moon is 7.0 degrees north-northeast of Spica at 16:00
2/15 Venus is at the ascending node through the ecliptic plane at 6:00; Mercury (magnitude +0.5) is 5.8 degrees west of Neptune (magnitude +8.0) at 21:00; Last Quarter Moon occurs at 22:18
2/16 Mercury is stationary in right ascension and begins retrograde motion at 10:00
2/17 Mercury stationary in longitude and begins retrograde motion at 1:00; the Sun enters Aquarius (longitude 327.9 degrees on the ecliptic) at 3:00; the Curtiss Cross, an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart, is predicted to be visible at 13:27
2/18 The Moon is 0.8 degree north of Mars, with an occultation occurring in the Azores, the southern portion of Greenland, northern South America, the Caribbean, most of Central America, and North America with the exception of western Canada and Alaska, at 13:00
2/19 The Moon is at the descending node (longitude 277.3 degrees) at 0:00; the Sun’s longitude is 330 degrees at 5:00; the Moon is 0.9 degree south of Jupiter, with an occultation occurring in southern South America and Antarctica, at 20:00
2/20 The Moon is 1.7 degrees south of Saturn at 14:00; Mars is at its southernmost declination (-23.7 degrees) at 16:00
2/22 Mercury is at its northernmost latitude from the ecliptic plane (7.0 degrees) at 10:00
2/23 New Moon (lunation 1202) occurs at 15:32
2/24 The Moon is 8.1 degrees southeast of Mercury at 1:00; the Moon is 3.8 degrees southeast of Neptune at 19:00
2/26 Mercury is in inferior conjunction with the Sun (0.637 astronomical units from the Earth, latitude 6.6 degrees) at 2:00; Jupiter is at the descending node through the ecliptic plane at 3:00; the Moon is at apogee, subtending 29' 25" from a distance of 406,278 kilometers (252,450 miles), at 11:34
2/27 The Moon is 5.8 degrees southeast of Venus at 18:00
2/28 The Moon is 4.0 degrees south of Uranus at 12:00

Nicolas Copernicus (1473-1543), Galileo Galilei (1564-1642), Jacques Cassini (1677-1756), William Huggins (1824-1910), John Dreyer (1852-1926), Bernard Lyot (1897-1952), and Clyde Tombaugh (1906-1997) were born this month.

Nicolas Louis de Lacaille discovered the open cluster NGC 3228 in Vela on February 11, 1752.  Nicolas Louis de Lacaille discovered the face-on barred spiral galaxy M83 in Hydra on February 23, 1752.  Johann Bode discovered the globular cluster M53 in Coma Berenices on February 3, 1775.  The planetary nebula M97 in Ursa Major was discovered by Pierre François André Méchain on February 16, 1781.  Caroline Herschel discovered the open cluster NGC 2360 in Canis Major on February 26, 1783.  William Herschel discovered the face-on barred spiral galaxy NGC 4027 in Corvus on February 7, 1785.  William Herschel’s 40-foot-focal-length telescope saw first light on February 19, 1787.  Clyde Tombaugh discovered Pluto on February 18, 1930.  James Hey detected radio waves emitted by the Sun on February 27, 1942.  Gerald Kuiper discovered the Uranian satellite Miranda (magnitude +15.8) on February 16, 1948.  The first pulsar, PSR B1919+21, was discovered by Jocelyn Bell Burnell and Antony Hewish on February 24, 1967.  Supernova 1987A was discovered by Ian Shelton, Oscar Duhalde, and Albert Jones on February 23, 1987. 

The zodiacal light should be visible from a dark location in the west after evening twilight for two weeks starting on February 11th.  Click on https://www.atoptics...ighsky/zod1.htm for more on the zodiacal light.

Information on passes of the ISS, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-a...ns-above.com/  

The Moon is 6.9 days old, is illuminated 37.9%, subtends 29.9', and is located in the constellation of Pisces at 0:00 UT on February 1st. The Moon attains its greatest northern declination (+23.2 degrees) for the month on February 7th and its greatest southern declination (-23.2 degrees) on February 19th.  Longitudinal libration is at a maximum of +6.6 degrees on February 17th and at a minimum of -7.0 degrees on February 5th.  Latitudinal libration is at a maximum of +6.6 degrees on February 26th and a minimum of -6.6 degrees on December 12th.  New Moon occurs on February 23rd.  The Moon is at perigee (a distance of 56.52 Earth-radii) on February 10th and is at apogee (a distance of 63.70 Earth-radii) on February 26th.  The Moon is about one degree from Graffias (Beta Scorpii) on the morning of February 16th.  The waning crescent Moon joins Mars, Jupiter, and Saturn in the southeastern sky on the mornings of February 18th, February 19th, and February 20th. The Lunar X occurs on February 1st and the Curtiss Cross on February 17th.  From certain parts of the world, the Moon occults 4 Vesta, 3 Juno, Mars, and Jupiter on February 2nd, February 13th, February 18th, and February 19th respectively.  Browse http://www.lunar-occ...ota/iotandx.htm for information on lunar occultation events.  Visit https://saberdoesthe...does-the-stars/ for tips on spotting extreme crescent Moons and http://www.curtrenz.com/moon06.html for Full Moon data.  Consult http://time.unitariu...oon/where.html  or download http://www.ap-i.net/avl/en/start for current information on the Moon.  See https://svs.gsfc.nasa.gov/4768 for a lunar phase and libration calculator and https://svs.gsfc.nasa.gov/4768 for the Lunar Reconnaissance Orbiter Camera (LROC) Quickmap.  Click on https://www.calendar...r/2020/february for a lunar phase calendar for this month. Times and dates for the lunar crater light rays predicted to occur this month are available at http://www.lunar-occ...o/rays/rays.htm

The Sun is located in the constellation of Capricornus on February 1st.  It enters Aquarius on February 16th.

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on February 1: Mercury (magnitude -1.0, 5.6", 85% illuminated, 1.19 a.u., Capricornus), Venus (magnitude -4.1, 15.3", 73% illuminated, 1.09 a.u., Aquarius), Mars (magnitude +1.4, 4.8", 93% illuminated, 1.95 a.u., Ophiuchus), Jupiter (magnitude -1.9, 32.5", 100% illuminated, 6.07 a.u., Sagittarius), Saturn (magnitude +0.6, 15.1", 100% illuminated, 10.97 a.u., Sagittarius), Uranus (magnitude +5.8, 3.5", 100% illuminated, 20.17 a.u. on February 15th, Aries), Neptune (magnitude +8.0, 2.2", 100% illuminated, 30.85 a.u. on February 15th, Aquarius), and Pluto (magnitude +14.4, 0.1", 100% illuminated, 34.81 a.u. on February 15th, Sagittarius). 

Mercury, Venus, and Neptune can be seen in the west and Uranus in the southwest in the evening sky.  In the morning sky, Mars, Jupiter, and Saturn lie in the southeast. 

Mercury, Venus, Mars, Jupiter, and Saturn all pass through the ecliptic during February.

Mercury is at the ascending node on February 7th.  It reaches greatest eastern elongation on February 10th and perihelion on February 12th.  This will be a short but respectable evening apparition of the planet for northern hemisphere observers with the planet positioned ten degrees above the horizon for the first two weeks of February.  Mercury will shine at brighter than zero magnitude during the first half of the month.  Mercury is stationary on February 16th and is at heliocentric latitude north on February 22th.  The speediest planet will dim dramatically as it approaches inferior conjunction on the evening of February 25th (February 26th UT). 

Venus increases 15 degrees in declination during the month, rising from nearly 35 degrees to slightly more than 41 degrees in altitude at sunset from 40 degrees north.  It decreases in illumination from 73 to 63% but grows in angular size from 15 to 19 arc seconds.  The brightest planet crosses the celestial equator on February 9th.  On February 15th, it’s at the ascending node.  The Moon passes six degrees north of Venus on February 27th.  Venus sets approximately three and three-quarters hours after the Sun by the end of the month. 

Mars passes the descending node of its orbit, moving to the south of the orbital plane of the Earth, and enters southern ecliptic latitudes on February 1st.  The apparent diameter of the planet exceeds five arc seconds on February 10th.  Mars enters Sagittarius on February 11th.  Mars passes between M8 (the Lagoon Nebula) and M20 (the Trifid Nebula) on February 17th.  The waning crescent Moon passes less than one degree north of Mars on February 18th.  A short article on the occultation that will occur for much of the continental United States, Canada, and parts of Central America can be found on page 50 of the February 2020 issue of Sky & Telescope.

As February begins, Jupiter rises 90 minutes before sunrise.  It brightens from magnitude -1.9 to magnitude -2.0 and increases in apparent diameter from 32.5 arc seconds to 34.1 arc seconds this month.  The waning crescent Moon passes just less one degree to the south of Jupiter on February 19th.  The gas giant planet is at the descending node on February 26th.  Data on Galilean satellite events is available online at http://www.shallowsky.com/jupiter/ and http://www.skyandtel...watching-tools/ and on page 51 of the February 2020 issue of Sky & Telescope.  Click on http://www.skyandtel...watching-tools/ or consult pages 50 and 51 of the February 2020 issue of Sky & Telescope to determine transit times of the central meridian by the Great Red Spot.

The Ringed Planet crosses the ecliptic on February 13th.  Saturn departs Sagittarius and enters Capricornus in the middle of the month.  The waning crescent Moon passes less than two degrees south of Saturn on February 20th.  As the month ends, Saturn’s ring system spans 35 arc seconds and is inclined 22 degrees from edge-on.  For information on the satellites of Saturn, browse http://www.skyandtel...watching-tools/

Uranus is located about 12 degrees south of the second-magnitude star Hamal (Alpha Arietis). The ice giant sets around midnight local time early in the month and about two hours earlier as February draws to a close. Uranus and Venus are separated by about eight degrees on February 29th.

Neptune lies six degrees west of Venus and 18 arc minutes west of the class M red giant star Phi Aquarii (magnitude 4.2) on February 1st.  By February 10th, Neptune is positioned just 2.3 arc minutes north of the star.  Mercury and Neptune are in quasiconjunction on February 15th.  Neptune disappears from view by the middle of the month.

See https://curtrenz.com/uranep.html for additional information on the two outer planets.

Finder charts for Uranus and Neptune are also available online at https://s22380.pcdn....020_updated.pdf

Click on http://www.skyandtel...watching-tools/ for JavaScript utilities that will illustrate the positions of the five brightest satellites of Uranus and the position of Triton, Neptune’s brightest satellite.

The dwarf planet Pluto is not visible this month.

A guide to planetary observing for the year by the British magazine The Sky at Night is posted at https://www.skyatnig...nets-night-sky/

For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/

Comet C/2017 T2 (PanSTARRS) is located a degree northwest of NGC 869 (the western half of the Double Cluster) on February 1st.  By the middle of February, the comet is located a degree to the west of the open cluster Stock 2 (the Muscle Man Cluster).  It can be found several degrees west of IC 1805 (the Heart Nebula) and IC 1848 (the Soul Nebula) as the month ends.  Comet PanSTARRS may brighten to magnitude +8.8 by the end of February.  An article and finder charts appear on pages 48 and 49 of the February 2020 issue of Sky & Telescope.  Visit http://cometchasing.skyhound.com/ and http://www.aerith.ne.../future-n.html  for additional information on comets visible this month.

Asteroid 4 Vesta shines at eighth magnitude as it exits Aries and enters Taurus this month.  The First Quarter Moon occults 4 Vesta on February 1st for observers in Alaska and western Canada.  Asteroids brighter than magnitude +11.0 that reach opposition this month include 37 Fides (magnitude +10.1) on February 2nd and 30 Urania (magnitude +10.6) on February 29th.  A finder chart for 37 Fides can be found on page 49 of the February 2020 issue of Sky & Telescope.  Consult http://asteroidoccul.../2020_02_si.htm for information on asteroid occultation events taking place this month.  Visit http://www.curtrenz.com/asteroids.html to learn more about a number of asteroids

A wealth of information on solar system celestial bodies is posted at http://www.curtrenz.com/astronomy.html and http://nineplanets.org/

The major meteor showers that will occur this year are discussed at https://www.skyandte...howers-in-2020/

Various events taking place within our solar system are discussed at http://www.bluewater...ed-4/index.html

Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtel...ky-at-a-glance/

A monthly podcast on various astronomical topics is available at https://www.skyandte...onomy-podcasts/

Free star maps for the month can be downloaded at http://www.skymaps.com/downloads.html and http://www.telescope...thly-Star-Chart

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on February 3rd, 6th, 9th, 11th, 14th, 17th, 20th, 23rd, 26th, and 29th.  Consult page 50 of the February 2020 issue of Sky & Telescope for the times of the minima.  The Demon Star is at minimum brightness for approximately two hours centered at 12:21 a.m. EST on February 6th (4:21 UT), at 9:10 p.m. EST on February 8th (2:10 UT on February 9th), at 10:55 p.m. EST on February 28th (3:55 UT on February 29th).  For more on Algol, see http://stars.astro.i.../sow/Algol.html and http://www.solstatio...rs2/algol3.htm 

Data on current supernovae can be found at http://www.rochester...y.org/snimages/

Information on observing some of the more prominent Messier galaxies is available at http://www.cloudynig...ur-astronomers/

Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and https://www.cambridg...s_january-march

Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.astro-tom...essier_maps.htm and http://sao64.free.fr...ataloguesac.pdf

Deep-sky object list generators can be found at https://dso-browser.com/ and http://www.virtualcolony.com/sac/ and http://tonightssky.com/MainPage.php

Free sky atlases can be downloaded at http://www.deepskywa...-atlas-full.pdf and https://allans-stuff.com/triatlas/

Forty binary and multiple stars for February: 41 Aurigae, Struve 872, Otto Struve 147, Struve 929, 56 Aurigae (Auriga); Nu-1 Canis Majoris, 17 Canis Majoris, Pi Canis Majoris, Mu Canis Majoris, h3945, Tau Canis Majoris (Canis Major); Struve 1095, Struve 1103, Struve 1149, 14 Canis Minoris (Canis Minor); 20 Geminorum, 38 Geminorum, Alpha Geminorum (Castor), 15 Geminorum, Lambda Geminorum, Delta Geminorum, Struve 1108, Kappa Geminorum (Gemini); 5 Lyncis, 12 Lyncis, 19 Lyncis, Struve 968, Struve 1025 (Lynx); Epsilon Monocerotis, Beta Monocerotis, 15 (S) Monocerotis (Monoceros); Struve 855 (Orion); Struve 1104, k Puppis, 5 Puppis (Puppis)

Notable carbon star for February: BL Orionis (Orion)

Fifty deep-sky objects for February: NGC 2146, NGC 2403 (Camelopardalis); M41, NGC 2345, NGC 2359, NGC 2360, NGC 2362, NGC 2367, NGC 2383 (Canis Major); M35, NGC 2129, NGC 2158, NGC 2266, NGC 2355, NGC 2371-72, NGC 2392, NGC 2420 (Gemini); NGC 2419 (Lynx); M50, NGC 2232, NGC 2237, NGC 2238, NGC 2244, NGC 2245, NGC 2251, NGC 2261, NGC 2264, NGC 2286, NGC 2301, NGC 2311, NGC 2324, NGC 2335, NGC 2345, NGC 2346, NGC 2353 (Monoceros); NGC 2169, NGC 2174, NGC 2194 (Orion); M46, M47, M93, Mel 71, NGC 2421, NGC 2423, NGC 2438, NGC 2439, NGC 2440, NGC 2467, NGC 2506, NGC 2509 (Puppis)

Top ten binocular deep-sky objects for February: M35, M41, M46, M47, M50, M93, NGC 2244, NGC 2264, NGC 2301, NGC 2360

Top ten deep-sky objects for February: M35, M41, M46, M47, M50, M93, NGC 2261, NGC 2362, NGC 2392, NGC 2403

Challenge deep-sky object for February: IC 443 (Gemini)


The objects listed above are located between 6:00 and 8:00 hours of right ascension.


https://www.cloudynights.com/topic/692689-february-2020-celestial-calendar/?p=9953136




January Celestial Calendar by Dave Mitsky

All times are UT (subtract five hours, and one calendar day when appropriate, for EST)

1/1   Asteroid 4 Vesta is stationary at 21:00
1/2   The Moon is at apogee, subtending 29' 32" from a distance of 404,580 kilometers (251,394 miles), at 1:30; Mercury is at its southernmost declination (-24.7 degrees) at 12:00; Mercury (magnitude -0.9) is 1.5 degrees south of Jupiter (magnitude -1.8) at 16:00; the Lunar X (the Purbach or Werner Cross), an X-shaped clair-obscure illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to be fully formed at approximately 20:39
1/3   First Quarter Moon occurs at 4:45; Mars and Uranus are at heliocentric opposition (longitudes 215.3 degrees and 35.3 degrees) at 12:00
1/4   The peak of the Quadrantid meteor shower (40 to 120 or more per hour) is predicted to occur at 9:00; the Moon is 4.3 degrees southeast of Uranus at 23:00
1/5   The latest sunrise of the year at latitude 40 degrees north occurs today; the Earth is at perihelion (147,091,144 kilometers or 91,398,199 miles distant from the Sun) at 7:48
1/7   The Moon is 7.3 degrees southeast of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 4:00; the Moon is 3.0 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 21:00
1/8   The latest onset of morning twilight of the year at latitude 40 degrees north occurs today
1/9   The Moon is 1.5 degrees southeast of the bright open cluster M35 in Gemini at 14:00; the Moon is at the ascending node (longitude 98.4 degrees) at 23:00
1/10  Mercury (1.43 astronomical units from the Earth at a latitude of -6.15 degrees) is in superior conjunction with the Sun at 15:00; a deep penumbral lunar eclipse visible from western Australia, Asia, Europe, Africa, extreme eastern South America, and extreme northern North America begins at 17:07; Full Moon (known as the Ice Moon, the Moon after Yule, the Old Moon, and the Wolf Moon) occurs at 19:21; the penumbral eclipse ends at 21:12; the Moon is 9.0 degrees south of the first-magnitude star Castor (Alpha Gemini) at 22:00
1/11 Uranus is stationary in longitude and resumes direct (i.e., eastward) motion at 0:00; the Moon is 5.3 degrees south of the first-magnitude star Pollux (Beta Gemini) at 3:00; Uranus is stationary in right ascension and resumes direct (i.e., eastward) motion at 6:00
1/12 The Moon is 1.0 degree north of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 0:00; Mercury (magnitude -1.2) is 2.0 degrees south of Saturn (magnitude +0.5) at 10:00
1/13 Pluto (at a distance of 34.94 astronomical units from the Earth at a latitude of -0.69 degree) is in conjunction with the Sun at 7:00; Saturn  (at a distance of 11.02 astronomical units from the Earth at a latitude of 0.04 degree) is in conjunction with the Sun at 15:00; asteroid 1 Ceres in in conjunction at 18:00; the Moon is at perigee, subtending 32’ 39" from a distance of 365,958 kilometers (227,396 miles), at 20:21
1/16 Asteroid 5 Astraea (magnitude +8.9) is at opposition in Cancer at 7:00
1/17 The Moon is 7.1 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 9:00; Last Quarter Moon occurs at 12:58
1/18 The Curtiss Cross, an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart, is predicted to be begin at 20:32
1/19 Mercury is at its southernmost latitude (-7.0 degrees) from the ecliptic plane at 12:00
1/20 The Sun enters Capricornus (longitude 299.7 degrees on the ecliptic) at 9:00; the Moon is 7.0 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 18:00; the Moon is 2.2 degrees north-northeast of Mars at 21:00
1/22 The Moon is at the descending node (longitude 278.4 degrees) at 21:00
1/23 The Moon is 0.4 degree south of Jupiter, with an occultation occurring in southwestern Polynesia, southern and eastern Melanesia, New Zealand, southern and eastern Australia, Kerguelen Island, and Madagascar at 3:00; the Moon is 0.4 degree southeast of Jupiter at 3:00; Uranus is at eastern quadrature (90 degrees from the Sun) at 7:00
1/24 New Moon (lunation 1201) occurs at 21:42
1/27 Venus (magnitude -4.1) is 0.08 degrees south of Neptune (magnitude +7.9) at 19:00
1/28 The Moon, Venus, and Neptune lie within a circle with a diameter of 3.9 degrees at 10:00; the Moon is 3.8 degrees southeast of Neptune at 10:00; the Moon is 3.8 degrees southeast of Venus at 10:00
1/29 The Moon is at apogee, subtending 29' 29" from a distance of 405,393 kilometers (251,899 miles), at 21:27

Johannes Hevelius (1611-1687), Ernst Abbe (1840-1905), George Van Biesbroeck (1880-1974), Luboš Kohoutek (1935), and Stephen Hawking (1942) were born this month.

Galileo Galilei discovered Io, Europa, and Callisto on January 7, 1610.  Galileo Galilei discovered Ganymede on January 13, 1610.  Nicolas-Louis de Lacaille discovered the emission nebula NGC 3372 (the Eta Carinae Nebula) on January 25, 1752.  Charles Messier discovered the globular cluster M56 on January 23, 1779.  Charles Messier discovered the globular cluster M80 on January 4, 1781.  William Herschel discovered the spiral galaxy NGC 1084 on January 10, 1785.  Pierre François André Méchain discovered Comet 2P/Encke on January 17, 1786.  William Herschel discovered Titania and Oberon, two satellites of Uranus, on January 11, 1787.  Giuseppe Piazzi discovered the first asteroid, 1 Ceres, on January 1, 1801.  Louis Daguerre took the first photograph of the Moon on January 2, 1839.  Alvan Clark discovered the white dwarf star Sirius B (the Pup) on January 31, 1862.  The 36-inch Clark refractor at the Lick Observatory saw first light on January 3, 1888.  Charles Perrine discovered the Jovian satellite Elara on January 2, 1905.  Philibert Jacques Melotte discovered the Jovian satellite Pasiphae on January 27, 1908.  Clyde Tombaugh photographed Pluto on January 23, 1930.  Mike Brown, Chad Trujillo, and David Rabinowitz discovered Eris on January 5, 2005.

The Quadrantid meteor shower is predicted to peak around 4:00 a.m. EST on January 4th.  The radiant lies at the junction of the constellations of Boötes, Hercules, and Draco, in what was once called Quadrans Muralis, and is highest just prior to dawn.  A waxing gibbous Moon will not compromise the peak of this year’s Quadrantids.  The Quadrantid shower can sometimes reach zenithal hourly rates of more than 100 meteors per hour for a relatively short period of time.  The near-Earth asteroid 2003 EH1, which may be an extinct comet, is believed to be the source of these meteors.  See pages 48 and 49 of the January 2020 issue of Sky & Telescope or https://amsmeteors.o...-meteor-shower/ for more on the Quadrantids.

Information on Iridium flares and passes of the ISS, the X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/ and https://www.calsky.c...=42301117054103

The Moon is 5.6 days old, is illuminated 28.1%, subtends 29.8 arc minutes, and is located in Aquarius on January 1st at 0:00 UT.  The Moon attains its greatest northern declination (+23.2 degrees) for the month on December 10th and greatest southern declination (-23.2 degrees) on December 23rd.  Longitudinal libration is at a maximum of +5.4 degrees on December 21st.  It’s at a minimum of -5.7 degrees on December 8th. Latitudinal libration is at a maximum of +6.9 degrees on December 3rd and +6.8 degrees on December 30th and a minimum of -6.8 degrees on December 16th. New Moon occurs on December 26th.  The Moon is at perigee (distance 57.38 Earth-radii) on January 13th and at apogee (distance 63.43 Earth-radii) on January 2nd and again (distance 63.56 Earth-radii) on January 29th.  A deep penumbral lunar eclipse, the 16th of Saros 144, reaches deepest eclipse in northwest India at 19:10:02 UT1 on January 10th.  At maximum, 92% of the Moon will lie within the Earth’s penumbra.  All four of the lunar eclipses that will occur in 2020 are penumbral.  See http://www.eclipsewi...ml#LE2020Jan10N for further information.  The Moon occults Jupiter on January 23rd from parts of the southern hemisphere.  New Moon occurs on January 24th.  Browse http://www.lunar-occ...ota/iotandx.htm for information on lunar occultation events.  Visit https://saberdoesthe...does-the-stars/ for tips on spotting extreme crescent Moons and http://www.curtrenz.com/moon06.html for Full Moon data.  Consult http://time.unitariu...oon/where.html  or download http://www.ap-i.net/avl/en/start for current information on the Moon.  See https://svs.gsfc.nasa.gov/4768 for a lunar phase and libration calculator and https://svs.gsfc.nasa.gov/4768 for the Lunar Reconnaissance Orbiter Camera (LROC) Quickmap.  Click on https://www.calendar...ar/2020/january for a lunar phase calendar for this month. Times and dates for the lunar crater light rays predicted to occur this month are available at http://www.lunar-occ...o/rays/rays.htm

The Sun is located in Sagittarius on January 1st.  It enters Capricornus on January 20th

Data (magnitude, apparent size, illumination, and distance from the Earth in astronomical units) for the planets and Pluto on January 1st: Mercury (-0.9, 4.7", 99%, 1.43 a.u., Sagittarius), Venus (-4.0, 13.1", 82%, 1.28 a.u., Capricornus), Mars (+1.6, 4.3", 96%, 2.18 a.u., Libra), Jupiter (-1.8, 31.8", 100%, 6.21 a.u., Sagittarius), Saturn (+0.5, 15.1", 100%, 11.00 a.u., Sagittarius), Uranus (+5.8, 3.6", 100%, 19.67 a.u. on January 16th, Aries), Neptune (+7.9, 2.2", 100%, 30.54 a.u. on January 1 6th, Aquarius), Pluto (+14.4, 0.1", 100%, 34.94 a.u. on January 16th, Sagittarius). 

During the evening, Mercury lies in the west, Venus and Neptune lie in the southwest, and Uranus lies in the south.  At midnight, Uranus is in the west.  Mars, Jupiter, and Saturn can be seen in the southwest in the morning. 

Mercury is at its greatest heliocentric latitude south on January 19th.  The speediest planet returns to the evening sky at twilight late in the month.  Mercury shines at magnitude -1.0 and sets approximately 70 minutes after sunset as January draws to a close.

Venus lies in the southwest at an altitude of approximately 25 degrees at sunset on January 1st.  Venus and Neptune undergo a very close conjunction on January 27th.  By January 31st, Venus has climbed to about 34 degrees above the horizon and sets about 3.5 hours after the Sun.  During January, Venus increases in apparent diameter from 13.2 arc seconds to 15.1 arc seconds but decreases in illumination from 82% to 74%. 

Earth is 0.9832 a.u. distant from the Sun at perihelion on January 5th.  On that date, it’s about 3% (5.0 million kilometers or 3.1 million miles) closer to the Sun than at aphelion on July 4th and about 2.7% closer to the Sun than on average.

Mars exits eastern Libra and enters Ophiuchus, Scorpius, and finally Sagittarius this month.  Mars passes less than five degrees northwest of Antares, the Rival of Mars, on the mornings of January 17th and January 18th.  Antares outshines Mars by about a half magnitude.  A waning crescent Moon passes two degrees north of Mars on January 20th. 

Jupiter appears low in the southeast during morning twilight after the second week of January.  It rises more than 90 minutes before sunrise by the end of the month.

Saturn is in conjunction with the Sun on January 13th and is not potentially visible again until the end of the month. 

Uranus is located 12 degrees south of the second-magnitude star Hamal (Alpha Arietis).  The First Quarter Moon passes five degrees south-southeast of Uranus on January 14th.  Uranus is at eastern quadrature on January 23rd.  The seventh planet sets around midnight as January comes to a close. Visit http://www.nakedeyep....com/uranus.htm for a finder chart.

Neptune is located just five arc minutes north of Venus, the closest conjunction of the two planets since January 1984, on January 27th.  It lies 12 arc minutes west of Venus a few hours later.  Browse and http://www.nakedeyep...com/neptune.htm for a finder chart.

Finder charts for Uranus and Neptune are also available online at https://s22380.pcdn....20_updated.pdf 

See http://www.curtrenz.com/uranep.html for additional information on the two outer planets.

Click on http://www.skyandtel...watching-tools/ for JavaScript utilities that will illustrate the positions of the five brightest satellites of Uranus and the position of Triton, Neptune’s brightest satellite. 

The dwarf planet Pluto is in conjunction with the Sun on January 13th.

For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/

Asteroid 4 Vesta shines at magnitude +7.5 as it heads northeastward through Cetus and Aries this month.  It is stationary on January 1st and passes less than one degree to the east of the fourth-magnitude Mu Ceti on January 12th.  Asteroids brighter than magnitude +11.0 that reach opposition this month include 192 Nausikaa (magnitude +10.0) on January 9th, 511 Davida (magnitude +9.6) on January 15th, 5 Astraea (magnitude +9.0) on January 21st, and 230 Athamantis (magnitude +10.7).  Finder charts for 5 Astraea and 511 Davida can be found on page 49 of the January 2020 issue of Sky & Telescope.  See http://asteroidoccul.../2020_01_si.htm for information on asteroid occultation events taking place this month.  Consult http://www.curtrenz.com/asteroids.html to learn more about a number of asteroids.

During January, Comet C/2017 T2 (PanSTARRS) heads northwestward along the border of Cassiopeia and Perseus. It lies less than one degree north of the fourth-magnitude star Eta Cassiopeia on January 13th and less than one degree north of NGC 869 and NGC 884 (the Double Cluster) on January 26th and January 27th.  Visit http://cometchasing.skyhound.com/ and http://www.aerith.ne...t/future-n.html for information on these and other comets visible this month.

A wealth of information on solar system celestial bodies is posted at http://www.curtrenz.com/astronomy.html and http://nineplanets.org/

The major meteor showers that will occur this year are discussed at https://www.skyandte...howers-in-2020/

Various events taking place within our solar system are discussed at http://www.bluewater...ed-4/index.html

Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtel...ky-at-a-glance/

Free star maps for January can be downloaded at http://www.skymaps.com/downloads.html and http://www.telescope...thly-Star-Chart

Omicron2 (40) Eridani is a fourth-magnitude triple star system consisting of three dwarf stars: a type K1V yellow-orange dwarf (A) known as Keid, a type DA4 white dwarf (B), and a type M4.5e red dwarf ©.  Omicron is located about 16 light years from the Earth at 4h15m16.32s, -7°39′10.34″.  Ninth-magnitude Omicron B is the most easily visible white dwarf star and can be seen with an aperture of six inches. 

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on January 2nd, 5th, 8th, 11th, 14th, 17th, 20th, 22nd, 25th, 28th, and 31st.  The Demon Star is at minimum brightness for approximately two hours and is well-placed for observers in North America on the night of January 14th, centered at 1:46 a.m. EST. Minima can also be observed on the night of January 16th, centered at 10:36 p.m. EST, and on the evening of January 19th, centered at 7:25 p.m. EST.  Consult page 50 of the January 2020 issue of Sky & Telescope for the times of the minima.  For more on Algol, see http://stars.astro.i.../sow/Algol.html and http://www.solstatio...rs2/algol3.htm 

Data on current supernovae can be found at http://www.rochester...y.org/snimages/

Information on observing some of the more prominent Messier galaxies is available at http://www.cloudynig...ur-astronomers/

Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and https://www.cambridg...s_january-march

Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.astro-tom...essier_maps.htm and http://sao64.free.fr...taloguesac.pdf 

Deep-sky object list generators can be found at https://dso-browser.com/ and http://www.virtualcolony.com/sac/ and http://tonightssky.com/MainPage.php


One hundred and five binary and multiple stars for January: Omega Aurigae, 5 Aurigae, Struve 644, 14 Aurigae, Struve 698, Struve 718, 26 Aurigae, Struve 764, Struve 796, Struve 811, Theta Aurigae (Auriga); Struve 485, 1 Camelopardalis, Struve 587, Beta Camelopardalis, 11 & 12 Camelopardalis, Struve 638, Struve 677, 29 Camelopardalis, Struve 780 (Camelopardalis); h3628, Struve 560, Struve 570, Struve 571, Struve 576, 55 Eridani, Struve 596, Struve 631, Struve 636, 66 Eridani, Struve 649 (Eridanus); Kappa Leporis, South 473, South 476, h3750, h3752, h3759, Beta Leporis, Alpha Leporis, h3780, Lallande 1, h3788, Gamma Leporis (Lepus); Struve 627, Struve 630, Struve 652, Phi Orionis, Otto Struve 517, Beta Orionis (Rigel), Struve 664, Tau Orionis, Burnham 189, h697, Struve 701, Eta Orionis, h2268, 31 Orionis, 33 Orionis, Delta Orionis (Mintaka), Struve 734, Struve 747, Lambda Orionis, Theta-1 Orionis (the Trapezium), Theta-2 Orionis, Iota Orionis, Struve 750, Struve 754, Sigma Orionis, Zeta Orionis (Alnitak), Struve 790, 52 Orionis, Struve 816, 59 Orionis, 60 Orionis (Orion); Struve 476, Espin 878, Struve 521, Struve 533, 56 Persei, Struve 552, 57 Persei (Perseus); Struve 479, Otto Struve 70, Struve 495, Otto Struve 72, Struve 510, 47 Tauri, Struve 517, Struve 523, Phi Tauri, Burnham 87, Xi Tauri, 62 Tauri, Kappa & 67 Tauri, Struve 548, Otto Struve 84, Struve 562, 88 Tauri, Struve 572, Tau Tauri, Struve 598, Struve 623, Struve 645, Struve 670, Struve 674, Struve 680, 111 Tauri, 114 Tauri, 118 Tauri, Struve 730, Struve 742, 133 Tauri (Taurus)

Notable carbon star for January: R Leporis (Hind’s Crimson Star)

Seventy deep-sky objects for January: B26-28, B29, M36, M37, M38, NGC 1664, NGC 1778, NGC 1857, NGC 1893, NGC 1907, NGC 1931 (Auriga); IC 361, Kemble 1 (Kemble’s Cascade asterism), NGC 1501, NGC 1502, NGC 1530, NGC 1569 (Camelopardalis); NGC 1507, NGC 1518, NGC 1531, NGC 1532, NGC 1535, NGC 1537, NGC 1600, NGC 1637, NGC 1659, NGC 1700 (Eridanus); IC 418, M79, NGC 1832, NGC 1888, NGC 1964 (Lepus); B33, Cr65, Cr69, Cr70, IC 434, M42, M43, M78, NGC 1662, NGC 1973-75-77, NGC 1981, NGC 1999, NGC 2022, NGC 2023, NGC 2024, NGC 2112 (Orion); Be11, NGC 1491, NGC 1496, NGC 1499, NGC 1513, NGC 1528, NGC 1545, NGC 1548, NGC 1579, NGC 1582, NGC 1605, NGC 1624 (Perseus); DoDz3, DoDz4, M1, Mel 25, NGC 1514, NGC 1587, NGC 1647, NGC 1746, NGC 1807, NGC 1817 (Taurus)

Top ten binocular deep-sky objects for January: Cr65, Kemble 1, M36, M37, M38, M42, NGC 1528, NGC 1647, NGC 1746, NGC 1981

Top ten deep-sky objects for January: M1, M36, M37, M38, M42, M43, M78, M79, NGC 1501, NGC 2024

Challenge deep-sky object for January: IC 2118 (Eridanus)


The objects listed above are located between 4:00 and 6:00 hours of right ascension.

December Celestial Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract five hours and, when appropriate, one calendar day for EST)

12/2   Asteroid 2 Pallas is in conjunction with the Sun at 2:00
12/4   The earliest end of evening twilight at 40 degrees north takes place today; the Lunar X (Purbach or Werner Cross), an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to occur at 06:44; First Quarter Moon occurs at 6:58
12/5   The Moon is at apogee, subtending 29' 33" from a distance of 404,446 kilometers (251,311 miles), at 4:08
12/7   The earliest sunset at latitude 40 degrees north occurs today
12/8   The Moon is 5 degrees north of Uranus at 11:00
12/10 The Moon is 7.3 degrees south of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 19:00
12/11 Venus is 1.8 degrees south of Saturn at 4:00; the Moon is 2.9 degrees north of the first-magnitude star Aldebaran (Alpha Taurii) at 11:00
12/12 Full Moon (known as the Before Yule, Cold, Long Nights, and Oak Moon) occurs at 5:12; Venus, Saturn, and Pluto lie within a circle with a diameter of 2.7 degrees at 19:00
12/13 The Moon is 1.5 degrees south of the bright open cluster M35 in Gemini at 4:00; the Moon is at the ascending node (longitude 98.4 degrees) at 14:00; Venus (magnitude -3.9) is 1.1 degrees south of Pluto (magnitude +14.3) at 16:00
12/14 The Moon is 5.3 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 18:00; the peak of the Geminid meteor shower (100 to 120 per hour) occurs at 19:00
12/15 The Moon is 1.0 degree north of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 16:00
12/16 Mercury is 5.0 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 7:00
12/17 The Moon is 3.7 degrees north of the first-magnitude star Regulus (Alpha Leonis) at 7:00
12/18 The Moon is at perigee, subtending 33' 16" from a distance of 370,265 kilometers (230,072 miles), at 20:25; the Sun enters the constellation of Sagittarius (ecliptic longitude 266.6 degrees) at 20:00
12/19 Mercury is at the descending node today; Last Quarter Moon occurs at 4:57; Venus is at its southernmost latitude from the plane of the ecliptic (-3.4 degrees) at 23:00
12/20 The Curtiss Cross, an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart, is predicted to be visible at 9:23
12/21 The Moon is 7.2 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 4:00
12/22 The Sun’s longitude is 270 degrees and winter solstice in the northern hemisphere occurs at 4:19
12/23 The Moon is 4.0 degrees south of Mars at 2:00; the peak of the Ursid meteor shower (5 to 10 per hour) occurs at 3:00
12/24 The Moon is 7.1 degrees north-northeast of Antares at 11:00
12/25 The Moon is 1.9 degrees north-northeast of Mercury at 12:00; the equation of time equals 0 (i.e., mean solar time equals apparent solar time) at 16:00
12/26 An annular solar eclipse visible from Saudi Arabia, the United Arab Emirates, Oman, southern India, Sri Lanka, Sumatra, Singapore, Borneo, part of the Philippines, and Guam begins at 3:43 and ends at 7:01; New Moon (lunation 1200) occurs at 5:13; the Moon is 0.3 degree northeast of Jupiter at 8:00; the Moon is at the descending node (longitude 278.4 degrees) at 13:00; the Moon is at its southernmost declination (-23.2 degrees) for the year at 20:00
12/27 The Moon is 1.2 degrees south of Saturn at 12:00; the Moon is 0.6 degree south of Pluto, with an occultation taking place in southern Madagascar, southernmost Africa, Kerguelen Island, portions of Antarctica, South Georgia, and southern South America, at 15:00; Jupiter is in conjunction with the Sun at 19:00
12/29 The Moon is 1.0 degree south of Venus, with an occultation taking place in southernmost South America and Antarctica, at 2:00
12/30 Mercury is at aphelion today; the middle of the eclipse season (i.e., the Sun is at the same longitude as the Moon’s descending node, 278.3degrees) occurs at 8:00

Tycho Brahe, Johannes Kepler, Isaac Newton, E. E. Barnard, and Arthur Eddington were born in December.

Giovanni Cassini discovered the Saturnian satellite Rhea on December 23, 1672. Nicolas Louis de Lacaille discovered NGC 2070 (the Tarantula Nebula) on December 5, 1751. The bright spiral galaxies M81 and M82 in Ursa Major were discovered by Johann Bode on December 31, 1774. William Herschel discovered the galaxy pair NGC 3166 and NGC 3169 in Sextans on December 19, 1783. Caroline Herschel discovered Comet 35P/Herschel-Rigoliet on December 21, 1788. Caroline Herschel discovered Comet C/1791 X1 (Herschel) on December 15, 1791. The Jovian satellite Himalia was discovered by Charles Perrine on December 3, 1905. Audouin Dolfus discovered the Saturnian satellite Janus on December 15, 1966. The Saturnian satellite Epimetheus was discovered by Richard Walker on December 18, 1966.

The peak of Geminid meteor shower occurs on the morning of December 14th but is adversely affected by moonlight from a bright waning gibbous Moon. The Geminids, which are associated with the Palladian asteroid, or possible cometary nucleus, 3200 Phaethon, have become the most reliable meteor shower of the year. Geminid meteors appear to originate from a radiant that’s just northwest of Castor (Alpha Geminorum). That radiant lies almost at the zenith at 2:00 a.m. local time. Geminid meteors travel at a relatively slow speed of 35 kilometers per second (22 miles per second). An article on this year’s Geminids can be found on pages 48 and 49 of the December 2019 issue of Sky & Telescope. The Ursids, a normally minor meteor shower with a maximum zenithal hourly rate of 10 per hour, peak on the morning of December 23rd and are not affected by a thin crescent Moon. A surge of up to 30 meteors per hour may occur this year. The radiant is located close to Kochab (Beta Ursa Minoris), some 15 degrees from the n celestial pole. See https://earthsky.org...d-meteor-shower and https://www.imo.net/...urces/calendar/ for additional information on the Geminids and https://earthsky.org/?p=2976 and https://www.imo.net/...urces/calendar/ for more on the Ursids. 

Information on Iridium satellite flares and passes of the ISS, the X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/

The Moon is 4.2 days old, is illuminated 19.1%, subtends 30.4 arc minutes, and is located in Virgo on December 1st at 0:00 UT. Due to the position of the ecliptic, the Moon reaches its highest point in the sky for the year in December. It attains its greatest northern declination (+23.2 degrees) for the month on December 14th and greatest southern declination (-23.2 degrees) on December 27th. Longitudinal libration is at a maximum of +5.0 degrees on December 26th. It’s at a minimum of -4.7 degrees on December 12th. Latitudinal libration is at a maximum of +6.8 degrees on December 7th and a minimum of -6.8 degrees on December 20th. New Moon occurs on December 26th. The Moon is at apogee (a distance of 63.41 Earth-radii) on December 5th and at perigee (a distance of 58.05 Earth-radii) on December 18th. The Moon occults Pluto on December 27th and Venus on December 29th from certain parts of the world. Consult http://www.lunar-occ...ota/iotandx.htm for more on these events. Visit http://saberdoesthes...does-the-stars/ for tips on spotting extreme crescent Moons and http://www.curtrenz.com/moon.html for Full Moon data. Browse http://www.cambridge...ft/the_moon.htm and http://www.shallowsky.com/moon/ for information on various lunar features. Click on https://www.calendar...r/2019/december for a lunar phase calendar for this month. Times and dates for the lunar crater light rays predicted to occur this month are available at http://www.lunar-occ...o/rays/rays.htm

The Sun is located in Ophiuchus, a non-traditional constellation of the zodiac, on December 1st. Sol enters Sagittarius on December 18th. Winter solstice for the northern hemisphere occurs when the Sun is farthest south for the year on December 21st. It is the shortest "day" of the year (9 hours and 20 minutes) at latitude 40 degrees north. An annular solar eclipse visible from western Australia, Asia, the Middle East, eastern Europe, extreme eastern Africa, the Indian Ocean, and the Pacific Ocean occurs on December 26th. It’s the 46th eclipse of 71 in Saros 132. Greatest eclipse takes place in eastern Sumatra (Indonesia) at 05:17:48 UT1 and has an annular duration of 3 minutes 39 seconds. For more on this event, consult http://www.eclipsewi...ml#SE2019Dec26A or page 49 of the December 2019 issue of Sky & Telescope.

Brightness, apparent size, illumination, distance from the Earth in astronomical units (a.u.), and location data for the planets and Pluto on December 1st: Mercury (magnitude -0.6, 6.3", 69% illuminated, 1.07 a.u., Libra), Venus (magnitude -3.9, 11.6", 89% illuminated, 1.44 a.u., Sagittarius), Mars (magnitude +1.7, 3.9", 98% illuminated, 2.39 a.u., Virgo), Jupiter (magnitude -1.8, 32.1", 100% illuminated, 6.15 a.u., Sagittarius), Saturn (magnitude +0.6, 15.4", 100% illuminated, 10.78 a.u., Sagittarius), Uranus (magnitude +5.7, 3.7", 100% illuminated, 19.18 a.u. on December 16th, Aries), Neptune (magnitude +7.9, 2.3", 100% illuminated, 30.05 a.u. on December 16th, Aquarius), and Pluto (magnitude +14.3, 0.1", 100% illuminated, 34.80 a.u. on December 16th, Sagittarius). 

During the evening, Venus, Jupiter, and Saturn can be found in the southwest, Uranus in the southeast, and Neptune in the south. Uranus is in the west at midnight. In the morning, Mercury and Mars are located in the southeast.

Venus, Saturn, and Pluto are all located in Sagittarius within a circle with a diameter of 2.7 degrees on December 12th.

A bright gibbous Mercury is visible in the southeastern morning sky in early December. By December 16th, the speediest planet will be too close to the Sun to be seen. It is at the descending node on December 19th. The Moon passes less than two degrees north-northeast of Mercury on December 25th. The closest planet to the Sun is at aphelion on December 30th. Mercury shrinks in apparent size from 6.3 to 4.9 arc seconds but increases in illumination from 69 to 99% during December.

Brilliant Venus climbs higher into the morning sky and Saturn sinks lower as the month unfolds. The bright globular cluster M22 lies less than one degree to the north of Venus on December 2nd. M75, another globular cluster, lies with one degree of Venus on the night of December 18th and December 19th. Venus and Saturn are five degrees apart on December 6th. The second-magnitude star Nunki (Sigma Sagittarii) is less than two degrees from Venus on that date. Venus passes less than two degrees from Saturn on December 11th. That distance increases to more than ten degrees by December 20th. Venus is at its heliocentric latitude south on December 20th. The Moon passes one degree south of the brightest planet on December 28th. Venus increases in apparent size to 13.0 arc seconds but decreases in illumination to 82% by December 31st.

A tiny Mars exits Virgo and enters Libra early in the month. It climbs higher in the morning sky and reaches an elongation of 40 degrees by the end of December. The Red Planet rises by more than three hours before the Sun as the year ends. Mars is four degrees south of the waning crescent Moon on the night of December 23rd.

Jupiter is lost in the glare of sunset by midmonth. The largest planet is in conjunction with the Sun on December 27th.

Saturn lies very low in the southwest during December. Saturn’s disk spans 15 arc seconds and its rings 35 arc seconds on December 1st. Its rings are tilted by 24 degrees. A slender crescent Moon passes 1.2 degrees south of the Ringed Planet on December 27th. 

Uranus lies in southern Aries near the border with Pisces, a region lacking in any bright stars.  Uranus is five degrees north of the Moon on December 8th. The gas giant planet attains an altitude of about 60 degrees in the south around 9:30 p.m. local time early in the month and doesn’t set until a few hours after midnight. Visit http://www.bluewater...anus_2019_1.pdf and http://www.nakedeyep....com/uranus.htm for finder charts.

Neptune is located 1.5 degree west-southwest of the fourth-magnitude star Phi Aquarii on the first day of the month. As December ends, Neptune lies 1.1 degrees from the star. The waxing gibbous Moon passes four degrees south of Neptune on 10th. Neptune sets before midnight this month.  Browse http://www.bluewater...tune_2019_1.pdf and http://www.nakedeyep...com/neptune.htm for finder charts.

Articles on Uranus and Neptune with finder charts appear on pages 48 and 49 of the September 2019 issue of Sky & Telescope and on pages 52 to 55 of the October issue of Astronomy. Finder charts for Uranus and Neptune are also available online at https://s22380.pcdn....020_updated.pdf

Click on http://www.skyandtel...watching-tools/ for JavaScript utilities that will illustrate the positions of the five brightest satellites of Uranus and the position of Triton, Neptune’s brightest satellite. 

Pluto will not be readily visible again until next year.

For more on the planets and how to locate them, see http://www.nakedeyeplanets.com/

Comet C/2017 T2 (PanSTARRS) may brighten to ninth magnitude as it heads northwestward along the border of Perseus and Camelopardalis. The comet passes just north of the open cluster NGC 1528 in Perseus on December 15th and through the faint emission nebula Sharpless 2-205. Visit http://cometchasing.skyhound.com/ and http://www.aerith.ne...t/future-n.html for information on comets that are visible this month. A list of the closest approaches of comets to Earth is posted at http://www.cometogra.../nearcomet.html

Asteroid 15 Eunomia shines at tenth magnitude as it travels northeastward through Aquarius this month. It passes 0.8 degree south of the third-magnitude star Alpha Aquarii on December 17th. During the final week of December, Eunomia glides through the Water Jar asterism, which consists of Gamma, Pi, Zeta, and Eta Aquarii. Asteroid 55 Pandora (magnitude +11.1) occults the 6.5-magnitude star 18 Aurigae for up to 7 seconds from Africa, southern United States, and Mexico on the evening of December 6th. Click on http://www.asteroido...07_55_62270.htm for additional information. Asteroids brighter than magnitude +11.0 reaching opposition this month include 97 Klotho (magnitude +10.1) on December 2nd, 28 Bellona (magnitude +10.5) on December 10th, 132 Aethra (magnitude +10.5) on December 14th, and 69 Hesperia (magnitude +10.5) on December 30th. For information on this year’s bright asteroids and upcoming asteroid occultation events, consult http://www.curtrenz.com/asteroids.html and http://asteroidoccultation.com/ respectively.

A wealth of current information on solar system celestial bodies is posted at http://nineplanets.org/ and http://www.curtrenz.com/astronomy.html

Various events taking place within our solar system are discussed at https://cosmicpursui...sky-this-month/ and http://www.bluewater...ed-4/index.html

Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtel...ky-at-a-glance/

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from +2.1 to +3.4, on December 2nd, 5th, 8th, 10th, 13th, 16th, 19th, 22nd, 25th, 28th, and 30th (UT dates). Algol is at minimum brightness for approximately two hours and is well-placed for observers in N America on the nights of December 4th (centered at 10:18 p.m. EST) and December 25th (centered at 12:02 a.m. EST). Consult page 50 of the December 2019 issue of Sky & Telescope for the times of the eclipses. For more on Algol, see http://stars.astro.i.../sow/Algol.html and

Free star charts for the month can be downloaded at http://www.skymaps.com/downloads.html and https://www.telescop...thly-Star-Chart and http://whatsouttonight.com/

Data on current supernovae can be found at http://www.rochester...y.org/snimages/

Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and http://www.cambridge...y-september.htm

Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.astro-tom...charts/map1.pdf and http://sao64.free.fr...ataloguesac.pdf respectively.

Information pertaining to observing some of the more prominent Messier galaxies can be found at http://www.cloudynig...ur-astronomers/

Author Phil Harrington offers an excellent freeware planetarium program for binocular observers known as TUBA (Touring the Universe through Binoculars Atlas), which also includes information on purchasing binoculars, at http://www.philharrington.net/tuba.htm

Stellarium and Cartes du Ciel are useful freeware planetarium programs that are available at http://stellarium.org/ and https://www.ap-i.net/skychart/en/start

Deep-sky object list generators can be found at http://www.virtualcolony.com/sac/ and http://tonightssky.com/MainPage.php and https://dso-browser.com/

Freeware sky atlases can be downloaded at http://www.deepskywa...-atlas-full.pdf and http://astro.mxd120....ee-star-atlases

One hundred and five binary and multiple stars for December: 
Gamma Andromedae, 59 Andromedae, Struve 245 (Andromeda)
Struve 362, Struve 374, Struve 384, Struve 390, Struve 396, Struve 400, Struve 19, Otto Struve 67 (Camelopardalis)
Struve 191, Struve Iota Cassiopeiae, Struve 263, Otto Struve 50, Struve 283, Struve 284 (Cassiopeia)
61 Ceti, Struve 218, Omicron Ceti, Struve 274, Nu Ceti, h3511, 84 Ceti, h3524, Lambda Ceti, Struve 330 (Cetus)
h3527, h3533, Theta Eridani, Rho Eridani, Struve 341, h3548, h3565, Tau-4 Eridani, Struve 408, Struve 411, h3589, h3601, 30 Eridani, 32 Eridani (Eridanus)
h3478, h3504, Omega Fornacis, Eta-2 Fornacis, Alpha Fornacis, See 25, Xi-3 Fornacis, h3596 (Fornax)
Struve 268, Struve 270, h1123, Otto Struve 44, h2155, Nu Persei, Struve 297, Struve 301, Struve 304, Eta Persei, Struve 314, Otto Struve 48, Tau Persei, Struve 331, Struve 336, Es588, Struve 352, Struve 360, Struve 369, Struve 382, Struve 388, Struve 392, Struve 410, Struve 413, Struve 425, Otto Struve 59, Struve 426, 40 Persei, Struve 434, Struve 448, Es277, Zeta Persei, Struve 469, Epsilon Persei, Es878 (Perseus)
Struve 399, Struve 406, Struve 401, Struve 422, Struve 430, Struve 427, Struve 435, 30 Tauri (Taurus)
Epsilon Trianguli, Struve 219, Iota Trianguli, Struve 232, Struve 239, Struve 246, 10 Trianguli, Struve 269, h653, 15 Trianguli, Struve 285, Struve 286, Struve 310 (Triangulum)

Notable carbon star for December: U Camelopardalis

One hundred deep-sky objects for December: 
NGC 891 (Andromeda)
IC 342, K6, St23, Tom 5 (Camelopardalis)
Be65, IC 1848, K4, Mel15, NGC 896, NGC 1027, St2, Tr3 (Cassiopeia)
M77, NGC 788, NGC 835, NGC 864, NGC 908, NGC 936, NGC 955, NGC 958, NGC 1015, NGC 1016, NGC 1022, NGC 1042, NGC 1052, NGC 1055, NGC 1087, NGC 1094 (Cetus)
IC 2006, NGC 1084, NGC 1140, NGC 1187, NGC 1199, NGC 1209, NGC 1232, NGC 1291, NGC 1300, NGC 1309, NGC 1332, NGC 1337, NGC 1353, NGC 1357, NGC 1395, NGC 1400, NGC 1407, NGC 1421, NGC 1426, NGC 1440, NGC 1452, NGC 1453, NGC 1461 (Eridanus)
NGC 1079, NGC 1097, NGC 1201, NGC 1292, NGC 1316 (Fornax I Galaxy Cluster), NGC 1317, NGC 1326, NGC 1344, NGC 1350, NGC 1360, NGC 1365, NGC 1371, NGC 1374, NGC 1379, NGC 1380, NGC 1381, NGC 1387, NGC 1398, NGC 1404, NGC 1406, NGC 1425 (Fornax)
Bas10, Cz8, IC 351, IC 2003, K5, Mel 20, M34, NGC 869, NGC 884, NGC 957, NGC 1023, NGC 1058, NGC 1161, NGC 1245, NGC 1275 (Perseus I Galaxy Cluster), NGC 1333, NGC 1342, NGC 1444, Tr2 (Perseus)
M45 (Taurus); NGC 777, NGC 784, NGC 890, NGC 925, NGC 949, NGC 959, NGC 978A/B (Triangulum)

Top ten binocular deep-sky objects for December: M34, M45, Mel15, Mel20, NGC 869, NGC 884, NGC 1027, NGC 1232, St2, St23

Top ten deep-sky objects for December: M34, M45, M77, NGC 869, NGC 884, NGC 891, NGC 1023, NGC 1232, NGC 1332, NGC 1360

Challenge deep-sky object for December: vdB14 (Camelopardalis)


The objects listed above are located between 2:00 and 4:00 hours of right ascension.



September Celestial Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)

9/1   The equation of time, which yields the difference between mean solar time and apparent solar time, equals 0 at 20:00

9/2   Mars is in conjunction with the Sun (2.675 astronomical units from Earth, latitude 1.7 degrees) at 11:00; the Moon is 7.1 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 15:00 

9/3   Mercury (magnitude -1.8) is 0.6 degree north-northeast of Mars (magnitude +1.7) at 17:00

9/4   Mercury is in superior conjunction with the Sun (1.369 AU from Earth, latitude 6.5 degrees) at 1:00

9/5   The Moon is 7.6 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 23:00

9/6   Asteroid 135 Hertha (magnitude +9.6) is at opposition in Aquarius at 6:00; First Quarter Moon occurs at 3:10; the Moon is 2.3 degrees north-northeast of Jupiter at 8:00; the Lunar X, also known as the Werner or Purbach Cross, an X-shaped clair-obscur illumination effect involving various ridges and crater rims located between the craters La Caille, Blanchinus, and Purbach, is predicted to begin at 15:47

9/8   The Moon is 0.04 degree north of Saturn, with an occultation taking place in western Melanesia, western Micronesia, western and northern Australia, southern Indonesia, Madagascar, and eastern Africa, at 14:00; Jupiter is at eastern quadrature (90 degrees from the Sun) at 15:00; the Moon is at the descending node (longitude 286.0 degrees) at 18:00

9/9   The Moon is 0.1 degree north of Pluto, with an occultation taking place in northern South America, the Galapagos Islands, Easter Island, and most of Polynesia with the exception of Hawaii, at 3:00

9/10 Neptune (magnitude +7.8, apparent size 2.4") is at opposition at 8:00

9/13 The Moon is at apogee, subtending 29' 24" from a distance of 406,377 kilometers (252,511 miles), at 1:32; Mercury is (magnitude -0.9) 0.3 degree south-southwest of Venus (magnitude -3.9) at 14:00; the Moon is 3.4 degrees southeast of Neptune at 21:00

9/14 Full Moon (known as the Barley, Corn, or Fruit Moon), this year’s Harvest Moon, occurs at 4:33

9/17 The Sun enters Virgo, at longitude 174.2 degrees on the ecliptic, at 8:00; the Moon is 4.0 degrees south of Uranus at 20:00

9/18 Saturn is stationary in right ascension, with prograde (direct) motion to commence, at 5:00; Saturn is stationary in longitude, with prograde (direct) motion to commence, at 7:00

9/19 The Moon is 7.6 degrees southeast the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 23:00; Mars and Neptune are at heliocentric opposition (longitudes 167.4 degrees and 347.4 degrees) at 23:00

9/20 The Moon is 2.6 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 16:00

9/22 Last Quarter Moon occurs at 2:41; the Moon is 2.0 degrees south of the bright open cluster M35 in Gemini at 9:00; the Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to be visible at 16:28; Mercury is at the descending node through the ecliptic plane at 21:00

9/23 The Moon is at the ascending node (longitude 104.4 degrees) at 7:00; the Sun is at a longitude of 180 degrees at 7:50; the autumnal equinox occurs in the northern hemisphere at 7:50; the Moon is 9.5 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 19:00

9/24 The Moon is 5.9 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 0:00; the Moon is 0.4 degree north of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 22:00

9/25 Asteroid 4 Vesta (magnitude +7.3) is stationary in Taurus at 5:00
9/26 The Moon is 3.2 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 11:00

9/27 Saturn is at its southernmost declination (-22.5 degrees) at 21:00

9/28 The Moon is at perigee, subtending 33' 24" from a distance of 357,803 kilometers (222,328 miles), at 2:24; asteroid 21 Lutetia (magnitude +9.0) is at opposition in Capricornus at 4:00; New Moon (lunation 1197) occurs at 18:26

9/29 Mercury (magnitude -0.2) is 1.3 degree north-northeast of Spica at 9:00; the Moon is 4.0 degrees north-northeast of Venus at 16:00

9/30 The Moon is 7.0 degrees north-northeast of Spica at 1:00; the Moon is 5.8 degrees north-northeast of Mercury at 3:00

Nicolas Louis de Lacaille and Johann Gottfried Galle were born this month.

Jean-Dominique Maraldi discovered the globular cluster M15 on September 7, 1746.
On September 11, 1746, Jean-Dominique Maraldi discovered the globular cluster M2. Nicolas-Louis de Lacaille discovered NGC 104 (47 Tucanae), the second largest and brightest globular cluster, on September 14th, 1751.
William Herschel discovered the barred spiral galaxy NGC 7753 on September 12, 1784. William Herschel discovered the Saturnian satellite Mimas on September 17, 1789.
Comet C/1793 S2 (Messier) was discovered by Charles Messier on September 27th, 1793. Karl Harding discovered asteroid 3 Juno on September 1, 1804.
Neptune was discovered by Johann Gottfried Galle on September 23, 1846, using Urbain Le Verrier’s calculations of its position.
On September 19, 1848, William Bond discovered Saturn’s fourteenth-magnitude satellite Hyperion, the first irregular moon to be discovered.
On September 13, 1850, John Russell Hind discovered the asteroid 12 Victoria.
E. E. Barnard discovered Jupiter’s fifth satellite, fourteenth-magnitude Amalthea, using the 36-inch refractor at the Lick Observatory, on September 9, 1892.

The minor meteor shower known as the Aurigids, which has a maximum hourly rate of just six per hour, peaks on the morning of September 1st. The peak of the minor meteor shower known as the Epsilon Perseids, with a maximum hourly rate of just five per hour, takes place on the evening of September 9th. The radiant is located near the second-magnitude star Algol (Beta Persei) at 03h15m, +40 degrees.

Information on passes of the ISS, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/

The Moon is 1.8 days old, subtends 33.3 arc minutes, is illuminated 3.8%, and is located in Virgo on September 1st at 0:00 UT. The Moon is at its greatest northern declination (+22.7 degrees) on September 23rd and its greatest southern declination (-22.5 degrees) on September 8th. Longitudinal libration is at a maximum of +7.9 degrees on September 5th and a minimum of -7.1 degrees on September 22nd. Latitudinal libration is at a maximum of +6.6 degrees on September 16th and a minimum of -6.6 degrees on September 2nd and -6.5 degrees on September 29th. The First Quarter Moon forms a noteworthy triangle with Antares and Jupiter on September 5th. The waxing gibbous Moon lies between Jupiter and Saturn on the following two nights. The waning gibbous Moon is located in the bright open cluster Melotte 25 (the Hyades) on the morning of September 20th. New Moon occurs on September 28th. Large tides will occur for several days thereafter. The Moon is at apogee (63.71 Earth-radii distant) on September 13th and at perigee (56.10 Earth-radii distant) on September 28th. The Moon occults Saturn on September 8th and Pluto on September 9th from certain parts of the world. The Moon occults the variable triple-star Propus (Eta Geminorum) for observers in the southwestern United States and Central America on the morning of September 22nd. For more on this event, see the article on page 50 of the September 2019 issue of Sky & Telescope. Browse http://www.lunar-occ...bstar/bstar.htm for information on this and other upcoming lunar occultations of bright stars. Visit http://saberdoesthes...s-the-stars/for tips on spotting extreme crescent Moons and http://www.curtrenz.com/moon06.html for Full Moon data. Click on https://www.calendar.../2019/septemberfor a lunar phase calendar for this month. Times and dates for the lunar crater light rays predicted to occur in September are available at http://www.lunar-occ...o/rays/rays.htm

The zodiacal light, or the false dawn, is visible about two hours before sunrise from a dark site for two weeks beginning on September 26th. It can be seen in Leo, Cancer, Gemini, and Taurus. Articles on the zodiacal light appear at http://www.atoptics....ighsky/zod1.htm and http://oneminuteastr...zodiacal-light/

The Sun is located in Leo on September 1st. It enters Virgo on September 17th. The Sun crosses the celestial equator from north to south at 7:50 UT on September 23rd, the date of the autumnal equinox. 

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on September 1st:
Mercury (magnitude -1.8, 5.0", 99% illuminated, 1.35 a.u., Leo),
Venus (magnitude -3.9, 9.7", 100% illuminated, 1.72 a.u., Leo),
Mars (magnitude +1.7, 3.5", 100% illuminated, 2.68 a.u., Leo),
Jupiter (magnitude -2.2, 39.0", 99% illuminated, 5.06 a.u., Ophiuchus),
Saturn (magnitude +0.3, 17.6", 100% illuminated, 9.42 a.u., Sagittarius),
Uranus (magnitude +5.7, 3.7", 100% illuminated, 19.09 a.u. on September 16th, Aries), Neptune (magnitude +7.8, 2.4", 100% illuminated, 28.93 a.u. on September 16th, Aquarius), and Pluto (magnitude +14.3, 0.1", 100% illuminated, 33.40 a.u. on September 16th, Sagittarius).

This month Mercury and Venus are located in the west, Jupiter in the southwest, Saturn in the south, and Neptune in the east during the evening. At midnight, Saturn can be found in the southwest, Uranus in the east, and Neptune in the south. Uranus is in the southwest and Neptune is in the west in the morning sky. 

Mercury is in superior conjunction on September 4th. It reappears in the evening sky as the month ends.

During September, Venus changes very little in apparent size and magnitude. After being lost in the glare of the Sun when it reached superior conjunction last month, Venus can be seen once again in the evening sky as September draws to a close.

Mars is in conjunction with the Sun on September 2nd, a week after reaching aphelion, and is about as far from the Earth as the Red Planet can get. Mars won’t be visible again until the third week of October.

Jupiter sets shortly after 10:00 p.m. DST by the end of September. It decreases in brightness to magnitude -2.0 and shrinks in angular diameter by 3.1 arc seconds this month. The First Quarter Moon passes two degrees north of Jupiter on September 6th. Jupiter is at eastern quadrature on September 8th. Transits by Io, starting at 8:04 p.m. EDT (0:04 UT September 5th), and its shadow, starting at 9:21 p.m. EDT (1:21 UT September 5th), take place on September 4th. A transit by Ganymede’s shadow occurs on September 5th, beginning at 11:22 p.m. EDT (3:22 UT September 6th). Ganymede passes 30 arc minutes due north of Callisto on the evening of September 19th. Information on Great Red Spot transit times and Galilean satellite events is available on pages 50 and 51 of the September 2019 issue of Sky & Telescope and online at http://www.skyandtel...watching-tools/ and https://www.projectp....com/jevent.htm

Saturn’s disk is 17 arc seconds in diameter at mid-month. At that time, its rings span 39 arc seconds and are tilted 25 degrees with respect to the Earth. Saturn fades from magnitude +0.3 to magnitude +0.5 this month. The Ringed Planet lies very close to the waxing gibbous Moon on September 8th, with an occultation occurring in some parts of the world. Saturn reaches its second stationary point on September 18th and then begins prograde or eastward motion. It is at its southernmost declination of -22.5 degrees on September 27th. Eighth-magnitude Titan, Saturn’s largest and brightest satellite, is due south of the planet on September 7th and due north of it on September 16th. Twelfth-magnitude Enceladus is located five arc seconds southwest of tenth-magnitude Tethys on September 4th. Saturn’s peculiar satellite Iapetus shines at eleventh magnitude on September 11th, when it is passes 1.4 arc minutes to the south of the planet. Iapetus brightens to tenth magnitude and is positioned 8.5 arc minutes from Saturn on September 30th. For further information on Saturn’s satellites, browse http://www.skyandtel...atching-tools/ 

Uranus is located in southwestern Aries, eleven degrees south of the second-magnitude star Hamal (Alpha Arietis). The planet lies 2.5 degrees south of the sixth-magnitude star 19 Arietis throughout the month. The waning gibbous Moon passes four degrees south of Uranus on September 17th. Visit  http://www.bluewater...anus_2019_1.pdf and http://www.nakedeyep....com/uranus.htm for finder charts.

Neptune is located seven arc minutes east of the fourth-magnitude star Phi Aquarii on the first day of September. By September 5th, the ice giant planet lies just 42 arc seconds east of that star. As the day begins on September 6th, Neptune is a mere 13 arc seconds from Phi. Neptune subtends just 2.4 arc seconds, shines at magnitude +7.8, and lies at a distance of 4.0 light hours when it reaches opposition on September 10th. At that time, it is six arc minutes west of Phi Aquarii. As the month ends, Neptune is positioned 40 arc minutes from the star. The waxing gibbous Moon passes four degrees south of Neptune on September 13th. Browse http://www.bluewater...tune_2019_1.pdf and http://www.nakedeyep...com/neptune.htm for finder charts.

An article on Uranus and Neptune with finder charts appears on pages 48 and 49 of the September 2019 issue of Sky & Telescope. Finder charts for Uranus and Neptune are also available online at https://s22380.pcdn....020_updated.pdf

Pluto is located near the Teaspoon asterism in northeastern Sagittarius at a declination of nearly -22.5 degrees. Finder charts can be found at http://www.bluewater...9/Pluto2019.jpg and on page 48 and 49 of the July 2019 issue of Sky & Telescope and on page 243 of the RASC Observer’s Handbook 2019.

For more on the planets and how to locate them, see http://www.nakedeyeplanets.com/

During September, Comet C/2018 W2 (Africano) travels through Perseus, Andromeda, and Pegasus, and enters Pisces. It is at perihelion on September 5th and reaches a maximum brightness of approximately ninth magnitude on September 25th. On September 28th, the rapidly moving comet passes very close to the eleventh-magnitude galaxy NGC 7743 in southern Pegasus. Browse http://cometchasing.skyhound.com/ and http://www.aerith.ne...t/future-n.html for further information on comets visible this month. Other sources of information include https://theskylive.com/comets and http://www.shopplaza...mets/comets.htm and http://britastro.org...arts_comet.html

Asteroid 1 Ceres heads southeastward between Ophiuchus and Scorpius during September. The dwarf planet shines at ninth magnitude as it passes 12 arc minutes north of the fifth-magnitude star Rho Ophiuchi on September 11th and 2.9 degrees north of the first-magnitude star Antares on September 15th. Asteroid 135 Hertha (magnitude +9.6) is at opposition in Aquarius on September 6th. Asteroid 21 Lutetia (magnitude +9.0) is at opposition in Capricornus on September 28th. Data on asteroid occultations taking place this month is available at http://www.asteroido.../2019_09_si.htm and http://www.poyntsour.../New/Global.htm

A wealth of current information on solar system celestial bodies is posted at http://nineplanets.org/ and http://www.curtrenz.com/astronomy.html

Various events taking place within our solar system are discussed at http://www.bluewater...ed-4/index.html

Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtel...ky-at-a-glance/

Online data generators for various astronomical events are available at https://astronomynow.com/almanac/ and https://calsky.com/

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in brightness from magnitude +2.1 to magnitude +3.4, on September 1st, 4th, 7th, 10th, 12th, 15th, 18th, 21st, 24th, 27th, and 30th. Consult page 49 of the September 2019 issue of Sky & Telescope for the minima times. On the morning of September 7th, Algol shines at minimum brightness (magnitude +3.4) for approximately two hours centered at 2:05 a.m. EDT (6:05 UT). It does the same at 10:54 p.m. EDT (2:54 UT September 10th) on the night of September 9th and 12:34 a.m. EDT (4:34 UT) on the morning of September 30th. For more on Algol, see http://stars.astro.i.../sow/Algol.html and http://www.solstatio...rs2/algol3.htm 

Free star charts for the month can be downloaded at http://www.skymaps.com/downloads.html and https://www.telescop...thly-Star-Chart and http://whatsouttonight.com/

Data on current supernovae can be found at http://www.rochester...y.org/snimages/

Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and http://www.cambridge...y-september.htm

Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.astro-tom...charts/map1.pdf and http://sao64.free.fr...ataloguesac.pdf respectively.

Information pertaining to observing some of the more prominent Messier galaxies can be found at http://www.cloudynig...ur-astronomers/

Author Phil Harrington offers an excellent freeware planetarium program for binocular observers known as TUBA (Touring the Universe through Binoculars Atlas), which also includes information on purchasing binoculars, at http://www.philharrington.net/tuba.htm

Stellarium and Cartes du Ciel are useful freeware planetarium programs that are available at http://stellarium.org/ and https://www.ap-i.net/skychart/en/start

Deep-sky object list generators can be found at http://www.virtualcolony.com/sac/ and http://tonightssky.com/MainPage.php and https://dso-browser.com/

Freeware sky atlases can be downloaded at http://www.deepskywa...-atlas-full.pdf and http://astro.mxd120....ee-star-atlases

Eighty binary and multiple stars for September:
12 Aquarii, Struve 2809, Struve 2838 (Aquarius);
Alpha Capricorni, Sigma Capricorni, Nu Capricorni, Beta Capricorni, Pi Capricorni, Rho Capricorni, Omicron Capricorni, h2973, h2975, Struve 2699, h2995, 24 Capricorni, Xi Capricorni, Epsilon Capricorni, 41 Capricorni, h3065 (Capricornus);
Kappa Cephei, Struve 2751, Beta Cephei, Struve 2816, Struve 2819, Struve 2836, Otto Struve 451, Struve 2840, Struve 2873 (Cepheus);
Otto Struve 394, 26 Cygni, h1470, h1471, Omicron Cygni, Struve 2657, 29 Cygni, 49 Cygni, 52 Cygni, 59 Cygni, 60 Cygni, 61 Cygni, Struve 2762 (Cygnus);
Struve 2665, Struve 2673, Struve 2679, Kappa Delphini, Struve 2715, Struve 2718, Struve 2721, Struve 2722, Struve 2725 (in the same field as Gamma Delphini), Gamma Delphini, 13 Delphini, Struve 2730, 16 Delphini, Struve 2735, Struve 2736, Struve 2738 (Delphinus);
65 Draconis, Struve 2640 (Draco);
Epsilon Equulei, Lambda Equulei, Struve 2765, Struve 2786, Struve 2793 (Equuleus);
1 Pegasi, Struve 2797, h1647, Struve 2804, Struve 3112, 3 Pegasi, 4 Pegasi, Kappa Pegasi, h947, Struve 2841, Struve 2848 (Pegasus);
h1462, Struve 2653, Burnham 441, Struve 2655, Struve 2769 (Vulpecula)

Notable carbon star for September: LW Cygni

Fifty deep-sky objects for September:
M2, M72, M73, NGC 7009 (Aquarius);
M30, NGC 6903, NGC 6907 (Capricornus);
B150, B169, B170, IC 1396, NGC 6939, NGC 6946, NGC 6951, NGC 7023, NGC 7160, NGC 7142 (Cepheus);
B343, B361, Ba6, Be87, Cr 421, Do9, IC 4996, M29, M39, NGC 6866, NGC 6871, NGC 6888, NGC 6894, NGC 6910, NGC 6960, NGC 6992, NGC 6994, NGC 6995, NGC 7000, NGC 7008, NGC 7026, NGC 7027, NGC 7039, NGC 7048, NGC 7063, NGC 7086 (Cygnus); NGC 6891, NGC 6905, NGC 6934, NGC 7006 (Delphinus);
NGC 7015 (Equuleus);
M15 (Pegasus);
NGC 6940 (Vulpecula)

Top ten binocular deep-sky objects for September: IC 1396, LDN 906, M2, M15, M29, M30, M39, NGC 6939, NGC 6871, NGC 7000

Top ten deep-sky objects for September: IC 1396, M2, M15, M30, NGC 6888, NGC 6946, NGC 6960, NGC 6992, NGC 7000, NGC 7009

Challenge deep-sky object for September: Abell 78 (Cygnus)


The objects listed above are located between 20:00 and 22:00 hours of right ascension.




August Celestial Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)

8/1 The Moon, Venus, and the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer lie within a circle having a diameter of 2.7 degrees at 1:00; the Moon is 0.6 degree northeast of M44 at 2:00; New Moon (lunation 1195) occurs at 3:12; Mercury is stationary in longitude, with direct (eastward) motion to begin, at 4:00; the Moon is 1.6 degrees north of Mars at 21:00

8/2   The Moon is at perigee, subtending 33' 15'' from a distance of 359,398 kilometers (223,320 miles), at 7:11; the Moon is 3.1 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 14:00

8/3   Venus is 0.3 degree south of M44 at 7:00

8/6   Asteroid 16 Psyche (magnitude +9.3) is at opposition at 4:00; the Moon is 7.3 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 6:00

8/7   The astronomical cross-quarter day known as Lammas or Lughnasadh occurs today; First Quarter Moon occurs at 17:31

8/8   The Lunar X, also known as the Werner or Purbach Cross, an X-shaped clair-obscur illumination effect involving various ridges and crater rims located between the craters La Caille, Blanchinus, and Purbach, is predicted to begin at 3:43; Mercury is 9.1 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 5:00; Venus is at perihelion (a distance of 0.7185 astronomical units from the Sun) at 9:00


8/9  The Moon is 7.7 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 17:00; the Moon is 2.0 degrees south of Jupiter at 23:00; Mercury is at greatest western elongation (19.0 degrees) at 23:00

8/11 The Sun enters Leo, at longitude 138.2 degrees on the ecliptic, at 3:00; Jupiter is stationary in right ascension, with direct (eastern) motion to begin, at 16:00

8/12 Uranus is stationary in right ascension, with retrograde (western) motion to begin, at 6:00; the Moon is 0.04 degree south of Saturn, with an occultation taking place in most of Polynesia, Melanesia, northern New Zealand, most of Australia, and eastern Indonesia, at 10:00; the Moon is at the descending node (longitude 287.4 degrees) at 15:00; Jupiter is 6.7 degrees northeast of Antares at 17:00; the Moon is 0.1 degree north of Pluto, with an occultation taking place in the southern Arabian Peninsula, central and eastern Africa, Ascension Island, and northeastern South America, 22:00

8/13 Asteroid 15 Eunomia (magnitude +8.2) is at opposition at 6:00; the peak of the Perseid meteor shower (a zenithal hourly rate of 150 or more per hour) occurs at 7:00

8/14 Venus is in superior conjunction with the Sun (1.731 astronomical units) at 6:00

8/15 Venus is at its brightest (magnitude -3.9) at 12:00; Full Moon (known as the Fruit, Grain, Green Corn, or Sturgeon Moon) occurs at 12:29: Mercury is at the ascending node through the ecliptic plane at 15:00

8/17 Asteroid 39 Laetitia (magnitude +9.1) is at opposition at 3:00; the Moon is at apogee, subtending 29' 25'' from a distance of 406,244 kilometers (252,429 miles), at 10:49; Mercury is 0.9 degree south of M44 at 11:00; the Moon is 3.5 degrees southeast of Neptune at 17:00

8/18 Mars is 0.7 degree north-northeast of Regulus at 9:00

8/20 Mercury is at perihelion (a distance of 0.3075 astronomical units from the Sun) at 7:00

8/21 Venus, Mars, and Regulus lie within a circle with a diameter of 2.1 degrees at 9:00; Venus is 0.9 degree north-northeast of Regulus 11:00; the Moon is 4.4 degrees southeast of Uranus at 19:00

8/22 Asteroid 4 Juno is in conjunction with the Sun at 22:00

8/23 Last Quarter Moon occurs at 14:56; the Moon is 7.8 degrees southeast of the bright open cluster M45 (the Pleiades or Subaru) at 17:00

8/24 The Curtiss Cross, an X-shaped clair-obscur illumination effect located between the craters Parry and Gambart, is predicted to be visible at 4:36; the Moon is 2.4 degrees north of the first-magnitude star Aldebaran (Alpha Taurii) at 10:00; Venus is 0.3 degree north-northeast of Mars at 18:00

8/26 Mars is at aphelion (1.6661 astronomical units from the sun) at 1:00; the Moon is 2.2 degrees south of the bright open cluster M35 in Gemini at 2:00

8/27 The Moon is at the ascending node (longitude 106.7 degrees) at 2:00; the Moon is 9.7 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 10:00; the Moon is 6.1 degrees south of Pollux at 15:00

8/28 The Moon is 0.3 degree north of M44 at 12:00

8/29 Mercury is 1.3 degrees north-northeast of Regulus at 9:00

8/30 The Moon, Mercury and Regulus lie within a circle having a diameter of 3.1 degrees at 0:00; the Moon is 3.1 degrees north-northeast of regulus at 1:00; Venus is at its northernmost latitude from the ecliptic plane (3.4 degrees) at 1:00; the Moon is 1.9 degrees north-northeast of Mercury at 3:00; New Moon (lunation 1196) occurs at 10:37; the Moon, Mercury and Mars lie within a circle having a diameter of 5.6 degrees at 11:00; Mercury is at its northernmost latitude from the ecliptic plane (7.0 degrees) at 12:00; the Moon is 2.9 degrees north-northeast of Mars at 13:00; the Moon, Venus, and Mars lie within a circle having a diameter of 4.00 degrees at 14:00; the Moon is at perigee, subtending 33' 28'' from a distance of 357,176 kilometers (221,939 miles), at 15:53; the Moon is 2.8 degrees north-northeast of Venus at 19:00

John Flamsteed, Christian Mayer, Pierre François André Méchain, Maria Mitchell, and Otto Struve were born this month.

The gibbous phase of Mars was first observed by Francesco Fontana on August 24, 1638. Abraham Ihle discovered the globular cluster M22 on August 26, 1665.
Nicolas Sarabat discovered Comet C/1729 P1 (Sarabat) on August 1, 1729.
Caroline Herschel discovered Comet C/1786 P1 (Herschel) on August 1, 1786.
The Saturnian satellite Enceladus was discovered by William Herschel on August 28, 1789. Dominique Dumouchel was the first person to observe the return of Comet 1P/Halley on August 5, 1835.
John Russell Hind discovered asteroid 7 Iris on August 13, 1847. Asaph Hall discovered Deimos on August 11, 1877 and Phobos on August 17, 1877.
The first extragalactic supernova, S Andromedae, was discovered by Ernst Hartwig on August 20, 1885.
David Jewitt and Jane Luu discovered the trans-Neptunian object (15760) 1992 QB1 on August 30, 1992.
The Jovian satellite 2002 Laomedeia was discovered by Matthew Holman on August 13th, 2002.

The peak of the Perseid meteor shower takes place on the night of August 12th/August 13th and is severely compromised by moonlight from a 95%-illuminated waxing gibbous Moon. Perhaps a dozen Perseids an hour may be visible during the peak. Comet 109P/Swift-Tuttle is the source of Perseid meteors. The shower’s radiant is just to the southeast of the Double Cluster (NGC 869 and NGC 884). For more on this year’s Perseids, see page 50 of the August 2019 issue of Sky & Telescope or click on https://earthsky.org...d-meteor-shower

Information on passes of the ISS, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/

The Moon is 29.3 days old, is illuminated 0%, subtends 33.1 arc minutes, and is located in Cancer on August 1st at 0:00 UT. The Moon is at its greatest northern declination on August 27th (+22.4 degrees) and its greatest southern declination on August 12th (-22.4 degrees). Longitudinal libration is at a maximum of +7.2 degrees on August 9th and a minimum of -7.3 degrees on August 25th. Latitudinal libration is at a maximum of +6.8 degrees on August 25th and a minimum of -6.7 degrees on August 6th. The Moon is at perigee (at a distance of 56.35 Earth-radii) on August 2nd and again (at a distance of 56.00 Earth-radii) on August 30th and at apogee (at a distance of 63.69 Earth-radii) on August 17th. New Moon (i.e., the dark of the Moon) occurs on August 1st and August 30th. Large tides will take place following New Moon on August 30th. The waxing gibbous Moon occults Saturn and Pluto on August 12th from certain parts of the world. The waning crescent Moon occults the third-magnitude star Zeta Taurii on the morning of August 25th. The event is visible from the western continental United States and Mexico. For more on this occultation, see page 50 of the August 2019 issue of Sky & Telescope.Browse http://www.lunar-occ...bstar/bstar.htm for information on upcoming lunar occultations. Visit http://saberdoesthes...does-the-stars/ for tips on spotting extreme crescent Moons. Click on https://www.calendar...dar/2019/august for a lunar phase calendar for this month. Times and dates for the lunar crater light rays predicted to occur in August are available at http://www.lunar-occ.../rays/rays.htm 

The Sun is located in Cancer on August 1st. It enters the constellation of Leo on August 11th and achieves an ecliptic longitude of 150 degrees on August 23rd.

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on August 1:
Mercury (magnitude +2.0, 9.7", 13% illuminated, 0.70 a.u., Gemini),
Venus (magnitude -3,9, 9.7", 100% illuminated, 1.73 a.u., Cancer),
Mars (magnitude +1.8, 3.5", 100% illuminated, 2.65 a.u., Leo),
Jupiter (magnitude -2.4, 42.7", 99% illuminated, 4.62 a.u., Ophiuchus),
Saturn (magnitude +0.2, 18.3", 100% illuminated, 9.11 a.u., Sagittarius),
Uranus (magnitude +5.8, 3.6", 100% illuminated, 19.53 a.u. on August 16th, Aries), Neptune (magnitude +7.8, 2.4", 100% illuminated, 29.02 a.u. on August 16th, Aquarius), and Pluto (magnitude +14.2, 0.1", 100% illuminated, 33.00 a.u. on August 16th, Sagittarius). 

This month Jupiter is visible in the south and Saturn in the southeast. At midnight, Jupiter and Saturn can be found in the southwest, Uranus in the east, and Neptune in the southeast. In the morning, Mercury is in the east, Uranus is in the south, and Neptune is in the southwest.  

Mercury undergoes one of its best morning appearances of the year beginning at the middle of August.  The speediest planet reaches its greatest heliocentric latitude south and is inferior conjunction on August 9th. The speediest planet is stationary on August 1st, reaches a greatest western elongation of 19 degrees on August 9th, and is at the ascending node on August 15th. It is at perihelion on August 20th and is at its greatest heliocentric latitude north on August 30th. The New Moon passes two degrees north-northeast of Mercury on August 30th.

Venus is lost in the glare of the Sun this month. It’s in superior conjunction with the Sun at ecliptic latitude 3.1 degrees on August 14th. On that date, Venus is 1.731 a.u. from the Earth. The brightest planet attains its greatest heliocentric latitude north on August 30th.

Mars is also too close to the Sun to be seen during August.

Jupiter sets around midnight local daylight-saving time by the end of the month. It decreases in brightness from magnitude -2.4 to magnitude -2.2 and diminishes in angular diameter from 42.7 to 39.1 arc seconds during August. Jupiter reaches its second stationary point on August 11th. At mid-month, the gas giant is situated approximately seven degrees from Antares. The waxing gibbous Moon passes two degrees south of Jupiter on August 9th. Jupiter passes very close to the tenth-magnitude globular cluster NGC 6235 from August 25th through August 27th. The four Galilean satellites are positioned in order of increasing distance from the planet on August 20th. Callisto, the outermost of the Galilean satellites, is located south of the planet on the night of August 16th/17th. Information on Great Red Spot transit times and Galilean satellite events is available on pages 50 and 51 of the August 2019 issue of Sky & Telescope and online at http://www.skyandtel...watching-tools/ and https://www.projectp...m/jevent.htm   

Saturn transits around 11:30 p.m. local daylight-saving time as August begins.  The Ringed Planet is located 0.6 degree south of the fourth-magnitude star Omicron Sagittarii on the night of August 7th/8th. Saturn is currently 18 arc seconds in angular diameter. Its ring system spans 41 arc seconds and is inclined by 25 degrees with respect to the Earth. The waxing gibbous Moon passes three degrees to the west of Saturn on August 11th. Saturn’s peculiar satellite Iapetus passes 1.4 arc minutes north of the planet and shines at eleventh magnitude on the night of August 4th/5th. For additional information on Saturn’s satellites, browse http://www.skyandtel...atching-tools/ 

Uranus lies eleven degrees southeast of the second-magnitude star Hamal (Alpha Arietis) this month. The ice giant is located 2.3 degrees south-southeast of the sixth-magnitude star 19 Arietis. Uranus is stationary in right ascension and begins retrograde (westward) motion on August 12th. The ice giant achieves its highest declination (+13 degrees) since the early 1960s on that date. A waning gibbous Moon passes five degrees south of the planet on August 21st. Visit http://www.bluewater...anus_2019_1.pdf and http://www.nakedeyep....com/uranus.htm for finder charts.

Neptune is located in eastern Aquarius. As the month begins, the eighth planet is situated 0.9 degree east-northeast of the fourth-magnitude star Phi Aquarii. By the end of August, Neptune lies just 0.15 degree from that star. A waning gibbous Moon passes four degrees south of Neptune on August 17th. Browse http://www.bluewater...tune_2019_1.pdf and http://www.nakedeyep...com/neptune.htm for finder charts.

Finder charts for Uranus and Neptune are also available at https://www.skyandte...WEB_UrNep19.pdf

The dwarf planet Pluto is occulted by a waxing gibbous Moon from some parts of the world on August 12th. On August 18th, Pluto passes 12 arc minutes north of the ninth-magnitude star HD 183431. On August 13th, Pluto can be found two arc minutes north of a tenth-magnitude field star. Finder charts can be found at http://www.bluewater...9/Pluto2019.jpgand on page 48 and 49 of the July 2019 issue of Sky & Telescope and on page 243 of the RASC Observer’s Handbook 2019.

For more on the planets and how to locate them, see http://www.nakedeyeplanets.com/

Comet C/2018 W2 (Africano) may shine at eleventh magnitude as it heads southwestward through Camelopardalis during August. It passes just to the north of the fifth-magnitude star SAO 24064 on August 29th. For further information on comets visible this month, browse http://cometchasing.skyhound.com/ and http://www.aerith.ne.../future-n.html 

Asteroid 15 Eunomia (magnitude +8.2) reaches opposition in Aquarius on August 13th, asteroid 16 Psyche (magnitude +9.3) reaches opposition in Capricornus on August 6th, and asteroid 39 Laetitia (magnitude +9.1) reaches opposition in Capricornus on August 16th. A finder chart showing all three asteroids appears on page 48 of the August 2019 issue of Sky & Telescope. For information on asteroid occultations taking place this month, see http://www.asteroido.../2018_08_si.htm

A wealth of current information on solar system celestial bodies is posted at http://nineplanets.org/
and http://www.curtrenz.com/astronomy.html

Various events taking place within our solar system are discussed at http://www.bluewater...ed-4/index.html

Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtel...ky-at-a-glance/

Free star charts for the month can be downloaded at http://www.skymaps.com/downloads.html and https://www.telescop...thly-Star-Chart

Data on current supernovae can be found at http://www.rochester...y.org/snimages/

Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and http://www.cambridge..._april-june.htm

Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.astro-tom...charts/map1.pdf and http://www.saguaroas...o110BestNGC.pdf respectively.

Information pertaining to observing some of the more prominent Messier galaxies can be found at http://www.cloudynig...ur-astronomers/

Author Phil Harrington offers an excellent freeware planetarium program for binocular observers known as TUBA (Touring the Universe through Binoculars Atlas), which also includes information on purchasing binoculars, at http://www.philharrington.net/tuba.htm

Stellarium and Cartes du Ciel are useful freeware planetarium programs that are available at http://stellarium.org/ and https://www.ap-i.net/skychart/en/start

Deep-sky object list generators can be found at http://www.virtualcolony.com/sac/ and http://tonightssky.com/MainPage.php and https://dso-browser.com/

Freeware sky atlases can be downloaded at http://www.deepskywa...-atlas-full.pdf and http://astro.mxd120....ee-star-atlases

Sixty binary and multiple stars for August:
5 Aquilae, Struve 2404, 11 Aquilae, Struve 2426, 15 Aquilae, Struve 2449, 23 Aquilae, Struve 2532, Pi Aquilae, 57 Aquilae (Aquila);
Beta Cygni (Albireo), 16 Cygni, Delta Cygni, 17 Cygni (Cygnus); 41 & 40 Draconis, 39 Draconis, Struve 2348, Sigma Draconis, Struve 2573, Epsilon Draconis (Draco);
95 Herculis, 100 Herculis, Struve 2289, Struve 2411 (Hercules);
Struve 2349, Struve 2372, Epsilon-1 & Epsilon-2 Lyrae (the Double-Double), Zeta-2 Lyrae, Beta Lyrae, Otto Struve 525, Struve 2470 & Struve 2474 (the Other Double-Double) (Lyra);
67 Ophiuchi, 69 Ophiuchi, 70 Ophiuchi, Struve 2276, 74 Ophiuchi (Ophiuchus);
Mu Sagittarii, Eta Sagittarii, 21 Sagittarii, Zeta Sagittarii, H N 119, 52 Sagittarii, 54 Sagittarii (Sagittarius);
Struve 2306, Delta Scuti, Struve 2373 (Scutum);
Struve 2296, Struve 2303, 59 Serpentis, Theta Serpentis (Serpens Cauda);
Struve 2445, Struve 2455, Struve 2457, 4 Vupeculae, Struve 2521, Struve 2523, Struve 2540, Struve 2586, Otto Struve 388, Struve 2599 (Vulpecula)

Notable carbon star for August: V Aquilae

Eighty deep-sky objects for August:
B139, B142, B143, NGC 6709, NGC 6738, NGC 6741, NGC 6751, NGC 6755, NGC 6772, NGC 6778, NGC 6781, NGC 6804, PK64+5.1 (Aquila);
 NGC 6819, NGC 6826, NGC 6834, (Cygnus); NGC 6643, NGC 6742 (Draco);
DoDz 9 (Hercules);
M56, M57, NGC 6703, NGC 6791, Ste1 (Lyra); NGC 6572, NGC 6633 (Ophiuchus);
H20, M71 (Sagitta);
B86, B87, B90, B92, B93, M8, M17, M18, M20, M21, M22, M23, M24, M25, M28, M54, M55, M69, M70, M75, NGC 6520, NGC 6544, NGC 6546, NGC 6553, NGC 6565, NGC 6603, NGC 6818, NGC 6822 (Sagittarius);
IC 4703, IC 4756, M16, NGC 6604 (Serpens Cauda);
B100, B101, B103, B104, B110, B111, B113, Bas 1, IC 1295, M11, M26, NGC 6649, NGC 6712 (Scutum);
Cr 399 (asterism), M27, NGC 6802, NGC 6823, NGC 6834, NGC 6940, St 1 (Vulpecula)

Top ten binocular deep-sky objects for August: Cr 399, IC 4756, M8, M11, M17, M22, M24, M25, M27, NGC 6633 (IC 4756 and NGC 6633 are collectively known as the Binocular Double Cluster)

Top ten deep-sky objects for August: M8, M11, M16, M17, M20, M22, M24, M27, M55, M57

Challenge deep-sky object for August: Abell 53 (Aquila)


The objects listed above are located between 18:00 and 20:00 hours of right ascension.
July Celestial Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)

7/1   The Moon is 1.6 degrees south-southeast of Venus at 23:00

7/2   Asteroid 18 Melpomene (magnitude +9.2) is at opposition at 1:00; New Moon (lunation 1194) occurs at 19:16; a total solar eclipse visible from the southern Pacific Ocean, northern Chile, and central Argentina reaches greatest eclipse at 19:22:53

7/3   The Moon is at the ascending node (longitude 107.6 degrees) at 7:00; the Moon is 6.1 degrees south of the first magnitude star Pollux (Beta Geminorum) at 18:00

7/4   The Moon is 0.1 degree north of Mars, with an occultation occurring in Micronesia, most of Asia, the Arabian Peninsula, and the eastern tip of Africa, at 6:00; the Moon is 3.3 degrees north-northeast of Mercury at 10:00; the Moon lies within the bright open cluster M44 (the Beehive or Praesepe) in Cancer at 15:00; the Earth is at aphelion (152,104,285 kilometers or 94,513,221 miles from the Sun) at 22:00

7/5   The Moon is at perigee, subtending 32' 51" at a distance of 363,726 kilometers (226,009 miles) at 5:00; Venus is at the ascending node through the ecliptic plane at 13:00

7/6   The Moon is 3.1 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 5:00

7/7   Mercury is stationary at 4:00; Venus is at its northernmost declination (23.4 degrees) at 5:00; Mercury is at aphelion at 7:00; Mercury (magnitude +2.0) is 4.0 degrees south of Mars (magnitude +1.8) at 14:00

7/9   First Quarter Moon occurs at 10:55; the Lunar X, also known as the Werner or Purbach Cross, an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to begin at 15:58; Saturn (magnitude +0.1, apparent size 18.4") is at opposition at 17:00

7/10 The Moon is 7.3 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 0:00; the middle of the eclipse season (i.e., the Sun is at same ecliptic longitude as the Moon’s ascending node, 107.5 degrees) occurs at 0:00

7/13 The Moon is 7.8 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 11:00; the Moon is 2.3 degrees north-northeast of Jupiter at 21:00

7/14 Pluto is at opposition (magnitude +14.2, apparent size 0.1") at 15:00

7/16 The Moon is 0.2 degree south of Saturn, with an occultation occurring in central South America, Easter Island, southern Polynesia, and eastern Melanesia, at 7:00; the Moon is at the descending node (longitude 287.7 degrees) at 9:00; the Moon is 0.04 degree south of Pluto, with an occultation occurring in western Micronesia, northern and central Australia, southern Indonesia, Madagascar, and eastern Africa, at 17:00; the Moon is at the descending node (longitude 287.7 degrees) at 9:00; a partial lunar eclipse visible from South America, Europe, Africa, most of Asia, and Australia reaches greatest eclipse at 21:30:44; Full Moon, known as the Hay or Thunder Moon, occurs at 21:38

7/18 Mars is at its greatest heliocentric latitude north today

7/19 The dwarf planet/asteroid 1 Ceres is stationary at 17:00

7/20 The Moon is at apogee, subtending 29' 28" from a distance of 405,481 kilometers (251,954 miles) at 23:59

7/21 The Sun enters Cancer, at longitude 118.3 degrees on the ecliptic, at 7:00; the Moon is 4.0 degrees south of Neptune at 8:00; Mercury reaches inferior conjunction at 12:00

7/22 Venus is 6.0 degrees south of Pollux at 17:00

7/23 The Sun’s ecliptic longitude is 120 degrees at 3:00

7/25 Last Quarter Moon occurs at 1:18; Mercury (magnitude +4.1) is 5.6 degrees south-southwest of Venus (magnitude -3.9) at 3:00; the Moon is 5.0 degrees south of Uranus at 7:00; the Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to be visible at 17:25

7/26 The equation of time, which yields the difference between mean solar time and apparent solar time, is at a minimum of -6.55 minutes, at 12:00

7/27 Mercury is at its greatest heliocentric latitude south today; the Moon is 7.9 degrees south-southeast of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 8:00

7/28 The Moon is 2.3 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 1:00

7/30 The Southern Delta Aquarid meteor shower (15 to 20 per hour) peaks; the Moon is at the ascending node (longitude 107.6 degrees) at 17:00

7/31 The Moon is 4.5 degrees north of Mercury at 4:00; the Moon is 6.1 degrees south of Pollux at 4:00;
Mercury is stationary at 19:00; the Moon is 0.7 degree northeast of Venus at 22:00

Friedrich Bessel (1784-1846) was born this month.

The light from Supernova SN 1054 was first noted by Chinese astronomers on July 4, 1054.
The first lunar map was drawn by Thomas Harriot on July 26, 1609.
Charles Messier discovered the globular cluster M28 in Sagittarius on July 27, 1764. Comet D/1770 L1 (Lexell) passed closer to the Earth than any comet in recorded history on July 1, 1770.
Charles Messier discovered the globular cluster M54 in Sagittarius on July 24, 1778. Caroline Herschel discovered the open cluster NGC 6866 in Cygnus on July 23, 1783.
The globular cluster NGC 6569 in Sagittarius was discovered by William Herschel on July 13, 1784.
Karl Ludwig Hencke discovered asteroid 6 Hebe on July 1, 1847.
The first photograph of a star, namely Vega, was taken on July 17, 1850.
The first photograph of a total solar eclipse was taken on July 28, 1851.
Henri-Alexandre Deslandres invented the spectroheliograph on July 24, 1853.
Sinope, one of Jupiter’s many satellites was discovered by Seth Nicholson on July 21, 1914.
Karl Jansky announced the detection of radio radiation from the center of the Milky Way on July 8, 1933.
Seth Nicholson discovered Neptune’s satellite Lysithea on July 6, 1938.
The Mariner 4 probe took the first close-up image of another planet, namely Mars, on July 14, 1965.
The Apollo 11 lunar module landed on the Moon on July 20, 1969.
Neptune’s satellites Despinea and Galatea are discovered using images from the Voyager 2 probe on July 27, 1989.
Fragments of Comet D/1993 F2 (Shoemaker-Levy) impacted Jupiter on July 16, 1994. Prospero, one of the satellites of Uranus, is discovered by Matthew Holman on July 18, 1999.
Pluto’s satellite Styx is discovered using images from the New Horizon probe on July 11, 2012.

The peak of the Southern Delta Aquarid meteor shower on the morning of July 30th is not compromised by moonlight. The radiant is located northwest of the first-magnitude star Fomalhaut (Alpha Piscis Austrini).  Southern hemisphere observers are favored. Click on http://earthsky.org/...d-meteor-shower for further information. Other minor meteor showers with southern radiants occurring this month are the Alpha Capricornids, the Piscis Austrinids, and the Northern Delta Aquarids.

Information on Iridium flares and passes of the ISS, the Tiangong-2, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/

The Moon is 27.4 days old, is illuminated 5.0%, subtends 31.3 arc minutes, and is located in Taurus on July 1st at 0:00 UT. The Moon is at its greatest northern declination of +22.4 degrees on July 3rd and +22.3 on July 30th and its greatest southern declination of -22.4 degrees on July 16th. Longitudinal libration is at a maximum of +6.0 degrees on July 12th and a minimum of -6.9 degrees on July 27th. Latitudinal libration is at a maximum of +6.8 degrees on July 24th and a minimum of -6.8 degrees on July 9th. New Moon takes place on July 2nd. The Moon is at perigee on July 5th (distance 57.03 Earth-radii) and at apogee on July 27th (distance 63.58 Earth-radii). The Moon forms a triangle with Jupiter and Antares on the night of July 12th and lies almost halfway between Jupiter and Saturn on July 14th. A partial lunar eclipse, the 22nd of Saros 139, takes place on July 16th, with greatest eclipse occurring at 21:30:44 UT. Approximately 65% of the Moon will be covered by the Earth’s shadow. The eclipse is not visible from North America. The Moon occults Mars and Saturn from various parts of the world on July 4th and July 16th respectively. See http://www.lunar-occ...ota/iotandx.htm for information on lunar occultations taking place in July. Visit http://saberdoesthes...does-the-stars/for tips on spotting extreme crescent Moons. Click on https://www.calendar...endar/2019/july for a lunar phase calendar for this month. The times and dates for the lunar crater light rays predicted to occur in July are available at http://www.lunar-occ.../rays/rays.htm 

The Sun is located in Gemini on July 1st. The Earth is farthest from the Sun on July 4th, when it is 3.3% more distant than it was at perihelion and 1.7% farther than its average distance. A total solar eclipse visible from the southern Pacific Ocean, northern Chile, and central Argentina occurs on July 2nd. This will be the 58th eclipse of Saros 127. Greatest eclipse takes place in the southern Pacific Ocean at 19:22:53 UT and lasts for 4 minutes and 33 seconds. A partial solar eclipse can be seen from most of South America and a small portion of Central America. Consult https://eclipse.gsfc...E2019Jul02T.GIF for further information. The Sun enters Cancer on July 21st. 

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on July 1st:
Mercury (+1.0 magnitude, 9.4", 27% illuminated, 0.72 a.u., Cancer)
Venus (-3.9 magnitude, 9.9", 98% illuminated, 1.68 a.u., Taurus)
Mars (+1.8 magnitude, 3.7", 99% illuminated, 2.56 a.u., Cancer)
Jupiter (-2.6 magnitude, 45.5", 100% illuminated, 4.34 a.u., Ophiuchus)
Saturn (+0.1 magnitude, 18.4", 100% illuminated, 9.05 a.u., Sagittarius)
Uranus (+5.8 magnitude, 3.5", 100% illuminated, 20.05 a.u. on July 16th, Aries) Neptune (+7.8 magnitude, 2.3", 100% illuminated, 29.35 a.u. on July 16th, Aquarius) Pluto (+14.2 magnitude, 0.1", 100% illuminated, 32.82 a.u. on July 16th, Sagittarius). 

Mercury is located in the west, Mars in the northwest, Jupiter in the south, and Saturn in the southeast during the evening. At midnight, Jupiter is in the southwest, Saturn is in the south, and Neptune is in the east. In the morning, Venus can be found in the northeast, Saturn in the southwest, Uranus in the east, and Neptune in the south. 

Mercury can be seen with difficulty low in west-northwest the evening sky in early July. A thin crescent Moon passes within three degrees of Mercury on July 4th. Mercury passes four degrees south of Mars on July 7th and less than six degrees south of Venus on July 25th. The speediest planet reaches inferior conjunction on July 21st.

Venus disappears into the glare of the Sun early in the month. It lies very low in the east-northeast at dawn on July 1st.

Mars is occulted by a thin crescent Moon from some parts of the world on July 4th. Mars is at its greatest heliocentric latitude north on July 18th.  By the end of the month, Mars subtends just 3.5 arc seconds.

Jupiter drops in brightness by two tenths of a magnitude and in apparent size by more than two arc seconds this month. The gas giant subtends 44.4 arc seconds at its equator and 41.6 arc seconds at its poles at mid-month. It culminates shortly before 11:30 p.m. local time at the beginning of the month and just after 9:00 p.m. local time as July ends. The waxing gibbous Moon passes two degrees to the north of Jupiter on the night of July 13th. Favorable EDT transits by Io and its shadow take place on the nights of July 4th, July 11th, July 18th, and July 27th. Io reappears from eclipse approximately 14 arc seconds from the eastern limb at approximately 11:48 p.m. EDT on July 12th. Europa transits the planet at a favorable EDT time on July 23rd. EDT transits by Ganymede occur on July 24th and July 31st. Information on Great Red Spot transit times and Galilean satellite events is available on pages 50 and 51 of the July 2019 issue of Sky & Telescope and online at http://www.skyandtel...watching-tools/ and https://www.projectp....com/jevent.htm

When Saturn reaches opposition on July 9th, it is located to the east of the Teapot asterism in Sagittarius. At that time, the Ringed Planet shines at magnitude +0.1, subtends 18.4 arc seconds at its equator and 16.9 arc seconds at its poles, has a declination of -22 degrees, and is 75 light minutes from the Earth. Saturn’s rings span 41.8 arc seconds at opposition and are tilted greater than 24 degrees with respect to the Earth. The average number of days between successive oppositions is 378. Saturn passes 1.1 degrees south of the third-magnitude star Pi Sagittarii on July 20th and 0.7 degree southeast of the fourth-magnitude star Omicron Sagittarii on July 31st. The gas giant attains a maximum altitude of approximately 28 degrees during July. Saturn is occulted by a nearly Full Moon from some parts of the world on July 16th. The faint satellite Enceladus shines at twelfth magnitude and is 16 arc seconds to the east of the edge of Saturn’s A ring on July 9th. Iapetus shines at tenth magnitude and is positioned 8.4 arc minutes west of Saturn on the same night. Eight-magnitude Titan and tenth-magnitude Tethys are also west of the planet, while tenth-magnitude Rhea and Dione lie to the north. For further data on Saturn’s satellites, browse http://www.skyandtel...watching-tools/

Uranus can be found in southern Aries approximately ten degrees southeast of the second-magnitude star Hamal (Alpha Arietis) and 2.3 degrees south of the sixth-magnitude star 19 Arietis. A waning crescent Moon passes five degrees south of Uranus on July 25th. Visit http://www.bluewater...anus_2019_1.pdf and http://www.nakedeyep....com/uranus.htm for finder charts.

Neptune is located in eastern Aquarius. The eighth planet is situated just east of the fourth-magnitude star Phi Aquarii at the start of the month. By the end of July, Neptune lies 0.9 degree from that star. A waning gibbous Moon passes four degrees south of Neptune on July 21st. Browse http://www.bluewater...tune_2019_1.pdfand http://www.nakedeyep...com/neptune.htm for finder charts.

Finder charts for Uranus and Neptune are also available at https://www.skyandte...WEB_UrNep19.pdf

The dwarf planet Pluto is at opposition in eastern Sagittarius on July 14th. It’s occulted by a nearly Full Moon from some parts of the world on July 16th. Finder charts can be found at http://www.bluewater...9/Pluto2019.jpg and on page 48 and 49 of the July 2019 issue of Sky & Telescope and on page 243 of the RASC Observer’s Handbook 2019.

A podcast on the planets this month can be heard at https://www.skyandte...cast-july-2019/

For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/

The periodic comet 168P/Hergenrother heads northeastward through the vicinity of Pisces, Cetus, and Aries during July. It may shine at only twelfth magnitude. See http://cometchasing.skyhound.com/ and http://www.aerith.ne...t/future-n.html for additional information on comets visible this month. 

The dwarf planet/asteroid 1 Ceres shines at eighth magnitude as it journeys southwestward through Libra. It lies within three degrees of the second-magnitude binary star Beta Scorpii for the entire month. Asteroids brighter than magnitude +11.0 reaching opposition this month include 18 Melpomene (magnitude +9.2) in Scutum on July 2nd and 45 Eugenia (magnitude +10.8) in Capricornus on July 26th. Information on asteroid occultations taking place this month is available at http://www.asteroido.../2019_07_si.htm

A wealth of current information on solar system celestial bodies is posted at http://nineplanets.org/ and http://www.curtrenz.com/astronomy.html

Various events taking place within our solar system are discussed at http://www.bluewater...ed-4/index.html

Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtel...ky-at-a-glance/

Free star charts for the month can be downloaded at http://www.skymaps.com/downloads.html and https://www.telescop...thly-Star-Chart

Data on current supernovae can be found at http://www.rochester...y.org/snimages/

Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and

Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.astro-tom...charts/map1.pdf and http://www.saguaroas...k110BestNGC.pdf respectively.

Information pertaining to observing some of the more prominent Messier galaxies can be found at http://www.cloudynig...ur-astronomers/

Stellarium and Cartes du Ciel are two excellent freeware planetarium programs that are available at http://stellarium.org/ and https://www.ap-i.net/skychart/en/start

Deep-sky object list generators can be found at http://www.virtualcolony.com/sac/ and http://tonightssky.com/MainPage.php and https://dso-browser.com/

Freeware sky atlases can be downloaded at http://www.deepskywa...-atlas-full.pdf and http://astro.mxd120....ee-star-atlases

The multiple star 36 Ophiuchi consists of three orange dwarf stars.  For more on this interesting system, see https://stardate.org...orange-triplets and http://www.solstatio...rs/36ophiu3.htm

Forty binary and multiple stars for July:

Eta Draconis, 17 & 16 Draconis, Mu Draconis, Struve 2273, Nu-1 & Nu-2 Draconis, Psi Draconis (Draco);

Kappa Herculis, Gamma Herculis, Struve 2063, 56 Herculis, Struve 2120, Alpha Herculis (Ras Algethi), Delta Herculis, Rho Herculis, Mu Herculis (Hercules);

Rho Ophiuchi, Lambda Ophiuchi, 36 Ophiuchi, Omicron Ophiuchi, Burnham 126 (ADS 10405), Struve 2166, 53 Ophiuchi, 61 Ophiuchi (Ophiuchus);

h5003 (Sagittarius);

Xi Scorpii, Struve 1999, Beta Scorpii, Nu Scorpii, 12 Scorpii, Sigma Scorpii, Alpha Scorpii (Antares), h4926 (Scorpius);

Struve 2007, 49 Serpentis, Struve 2031 (Serpens Caput);

53 Serpentis, Struve 2204, h4995, h2814 (Serpens Cauda);

Epsilon Ursae Minoris (Ursa Minor)

Notable carbon star for July: T Draconis

Sixty-five deep-sky objects for July:

NGC 6140, NGC 6236, NGC 6340, NGC 6395, NGC 6412, NGC 6503, NGC 6543 (Draco);

IC 4593, M13, M92, NGC 6106, NGC 6166, NGC 6173, NGC 6181, NGC 6207, NGC 6210, NGC 6229, NGC 6482 (Hercules);

B61, B62, B63, B64, B72, IC 4634, IC 4665, LDN 42, LDN 1773, M9, M10, M12, M14, M19, M62, M107, NGC 6284, NGC 6287, NGC 6293, NGC 6304, NGC 6309, NGC 6356, NGC 6366, NGC 6369, NGC 6384, NGC 6401, Tr 26 (Ophiuchus);

NGC 6440, NGC 6445 (Sagittarius);

B50, B55, B56, Cr 316, M4, M6, M7, M80, NGC 6144, NGC 6153, NGC 6192, NGC 6231, NGC 6242, NGC 6302, NGC 6337, NGC 6451 (Scorpius);

NGC 6217, NGC 6324 (Ursa Minor)

Top ten binocular deep-sky objects for July: IC 4665, LDN 1773, M4, M6, M7, M10, M12, M13, M92, NGC 6231

Top ten deep-sky objects for July: M4, M6, M7, M10, M12, M13, M92, NGC 6210, NGC 6231, NGC 6543

Challenge deep-sky object for July: NGC 6380 (Scorpius)


The objects listed above are located between 16:00 and 18:00 hours of right ascension.



June Celestial Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)

6/1   The Moon is 3.1 degrees south-southeast of Venus at 21:00

6/2   The Moon is 7.9 degrees south-southeast of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 13:00

6/3   Mercury is at its greatest heliocentric latitude north today; asteroid 2 Pallas is stationary at 2:00; the Moon is 2.3 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 6:00; New Moon (lunation 1193) occurs at 10:02

6/4   The Moon is 3.7 degrees south of Mercury at 17:00

6/5   A double Galilean satellite shadow transit (Ganymede’s shadow precedes Io’s) begins at 0:29; the Moon is 1.6 degrees south of Mars at 15:00; the Moon is at the ascending node (longitude 107.9 degrees) at 23:00

6/6   Mercury is 1.2 degrees north of the bright open cluster M35 in Gemini at 1:00; the Moon is 6.2 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 10:00

6/7   The Moon makes a close approach to the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 8:00; the Moon is at perigee, subtending 32' 26" from a distance of 368,504 kilometers (228,978 miles), at 23:15

6/8   The Moon is 3.0 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 22:00

6/9   Venus is 5.1 degrees south-southeast of the bright open cluster M45 at 5:00

6/10 The Purbach Cross or Lunar X, an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to be visible at 4:17; First Quarter Moon occurs at 5:59; Jupiter (magnitude -2.5, apparent size 46.0") is at opposition at 16:00

6/12 A double Galilean satellite shadow transit (Io’s shadow precedes Ganymede’s) begins at 3:33; the Moon is 7.3 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 18:00

6/13 The equation of time, which yields the difference between mean solar time and apparent solar time, equals 0 at 10:00

6/14 The earliest sunrise of the year at latitude 40 degrees north occurs today

6/15 The Moon is 0.9 degree north of dwarf planet/asteroid 1 Ceres, with an occultation taking place in Japan, northern and eastern China, northeastern Kazakhstan, and central and eastern Russia, at 15:00

6/16 The Moon is 7.8 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 5:00; the Moon is 2.0 degrees north-northeast of Jupiter at 20:00

6/17 The earliest morning twilight of the year at latitude 40 degrees north occurs today; Full Moon, known as the Rose or Strawberry Moon, occurs at 8:31; Venus is 5.0 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 21:00

6/18 Mercury (magnitude +0.2) is 0.2 degree north of Mars (magnitude +1.8) at 14:00

6/19  The Moon is at the descending node (longitude 287.6 degrees) at 2:00; the Moon is 0.4 degree south of Saturn, with an occultation taking place in southern Africa, the Antarctic Peninsula, southern South America, and Easter Island, at 4:00; the Moon is 0.1 degree south of Pluto, with an occultation taking place in western South America, Central America, southern Polynesia, southern Micronesia, northeastern Australia, and Melanesia, at 11:00; Mercury is 5.4 degrees south-southwest of Pollux at 14:00

6/21 Mars is 5.5 degrees south of Pollux at 8:00; the Sun reaches an ecliptic longitude of 90 degrees and the northern hemisphere summer solstice occurs at 15:56

6/22 The Sun enters Gemini, at longitude 90.43 degrees on the ecliptic, at 3:00; Neptune is stationary at 4:00

6/23 The Moon is at apogee, subtending 29' 32" from a distance of 404,548 kilometers (251,375 miles), at 7:50; Mercury is at greatest eastern elongation (25 degrees) at 23:00

6/24 The latest evening twilight of the year at latitude 40 degrees north occurs today; the Moon is 3.6 degrees south-southeast of Neptune at 4:00

6/25 Last Quarter Moon occurs at 9:47

6/26 Mercury is at the descending node today; the Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to be visible at 6:33

6/27 The latest sunset of the year at latitude 40 degrees north occurs today

6/28 The Moon is 4.5 degrees south-southeast of Uranus at 2:00

6/29 The Moon is 7.9 degrees south-southeast of the bright open cluster M45 at 23:00

6/30 The Moon is 2.3 degrees north of Aldebaran at 15:00

Giovanni Cassini (1625-1712), John Dollond (1706-1761), Charles Messier (1730-1817), William Lassell (1799-1880), George Ellery Hale (1868-1938), and Carolyn Shoemaker (1929) were born this month.

The British astronomer Edmund Halley discovered M13 on June 1, 1714.  The French astronomer Nicolas Louis de Lacaille discovered the globular cluster M55 on June 16, 1752.  A transit of the Sun by Venus was observed by Austrian, British, and French astronomers from various parts of the world on June 6, 1761.  The French astronomer Charles Messier discovered the globular cluster M14 on June 1st, 1764, the emission and reflection nebula M20 (the Trifid Nebula) on June 5, 1764, and the open cluster M23 on June 20, 1764.  The globular cluster M62 was discovered by Charles Messier on June 7, 1771.  The French astronomer Pierre Méchain discovered his first deep-sky object, the spiral galaxy M63 (the Sunflower Galaxy), on June 14, 1779.  The German/English astronomer William Herschel discovered the globular cluster NGC 6288 on June 24, 1784.  Neptune was independently discovered by the British astronomer John Couch Adams on June 5, 1846.  The Italian astronomer Giovanni Battista Donati discovered Comet C/1858 L1 (Donati), the first comet to be photographed, on June 2, 1858. A large storm on Saturn was observed by the American astronomer E. E. Barnard.  The Tunguska event occurred on June 30, 1908.  The largest known solar flare was recorded on June 27, 1984.  The Georgian astronomer Givi Kimeridze discovered a Type Ia supernova in the spiral galaxy M58 on June 28, 1989.  Namaka, a satellite of the dwarf planet Haumea, was discovered on June 30, 2005.  Kerberos, Pluto’s fourth satellite, was discovered by the Hubble Space Telescope team on June 28, 2011.

The minor Boötid meteor shower (5 per hour) peaks on the morning of June 27th.  The source of Boötid meteors is the periodic comet 7P/Pons-Winnecke.  The radiant lies in northern Boötes at right ascension 14 hours 56 minutes, declination 48 degrees.  Browse http://www.spaceweat...unebootids.html for additional information.
Information on Iridium flares and passes of the ISS, the Tiangong-2, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/

The Moon is 26.9 days old, is illuminated 7.6%, subtends 30.3 arc minutes, and is located in Cetus on June 1st at 0:00 UT.  The June lunar month is 29 days 09 hours 14 minutes in length.  The Moon is at its greatest northern declination of +22.2 degrees on June 6th and at its greatest southern declination of -22.3 degrees on June 19th.  Longitudinal libration is at a maximum of +5.1 degrees on June 16th and a minimum of -5.2 degrees on June 2nd and -6.1 degrees on June 29th.  Latitudinal libration is at a maximum of +6.8 degrees on June 27th and a minimum of -6.7 degrees on June 12th.  New Moon occurs on June 3rd.  On June 7th, the Moon passes very near the bright open cluster M44.  The Moon is at perigee on June 7th (distance 57.78 Earth-radii) and at apogee on June 23rd (distance 63.43 Earth-radii).  The Moon occults 1 Ceres on June 15th and Saturn and Pluto on June 19th from certain parts of the world.  See http://www.lunar-occ...ota/iotandx.htm for information on lunar occultations taking place this month.  Visit http://saberdoesthes...does-the-stars/ for tips on spotting extreme crescent Moons.  Click on http://www.calendar-...endar/2019/june for a lunar phase calendar.  Times and dates for the lunar light rays predicted to occur this month are available at http://www.lunar-occ...o/rays/rays.htm

The Sun is located in Taurus on June 1st.  It enters Gemini on June 22nd.  The Sun reaches its farthest position north for the year on June 21st.  There are 15 hours and one minute of daylight at latitude 40 degrees north on June 21st, the day of the summer solstice.  At latitude 40 degrees north, the earliest sunrise occurs on June 14th and the latest sunset on June 27th.  For an explanation of why this occurs, click on https://earthsky.org/?p=4027

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on June 1st:
Mercury (-1.1, 5.5", 87% illuminated, 1.23 a.u., Taurus),
Venus (magnitude -3.8, 10.5", 94% illuminated, 1.59 a.u., Aries),
Mars (magnitude +1.8, 3.9", 98% illuminated, 2.43 a.u., Gemini),
Jupiter (magnitude -2.6, 45.8", 100% illuminated, 4.30 a.u., Ophiuchus),
Saturn (magnitude +0.3, 18.0", 100% illuminated, 9.25 a.u., Sagittarius),
Uranus on June 16th (magnitude +5.9, 3.4", 100% illuminated, 20.49 a.u., Aries), Neptune on June 16th (magnitude +7.9,  2.3", 100% illuminated, 29.82 a.u., Aquarius), and Pluto on June 16th (magnitude +14.2, 0.1", 100% illuminated, 32.93 a.u., Sagittarius). 

Mercury and Mars are in the northwest and Jupiter is in the southeast in the evening sky.  At midnight, Jupiter lies in the south and Saturn lies in the southeast.  Venus in the northeast, Jupiter and Saturn can be found in the southwest, Uranus in the east, and Neptune in the southeast at dawn. 

Mercury grows in apparent size from 5.5 to 9.2 arc seconds but decreases in magnitude from -1.1 to +0.9.  Mercury reaches its highest heliocentric latitude on June 3rd.  On June 4th, a very thin two-day-old waxing crescent Moon passes four degrees south of the planet at sunset.  Mercury is located 1.2 degrees north of the bright open cluster M35 on June 8th.  Mercury and Mars are separated by 28 arc minutes on June 17th and just 18 arc minutes during their closest conjunction in 13 years on June 18th.  Mercury shines at magnitude +0.2, which is five times brighter than the Red Planet, and subtends 7.4 arc seconds, which is twice the apparent size of Mars at the time.  As June progress, Mercury climbs higher into the sky and Mars loses altitude.  The speediest planet reaches its greatest eastern elongation on June 23rd, when it is located at an altitude of 11 degrees 30 minutes after sunset. 

Brilliant Venus and the waning crescent Moon lie six degrees apart and six degrees above the horizon 30 minutes before sunrise on June 1st.  The planet is at an elongation of 20 degrees at the time.  Aldebaran is approximately five degrees to the lower right of Venus on the morning of June 18th.  Venus is just three degrees above the horizon one half-hour before the Sun rises on June 30th.

During June, Mars shines faintly at magnitude +1.8 and shrinks to 3.7 arc seconds, just three arc seconds larger than Uranus.  The waxing crescent Moon passes 1.6 degrees south of Mars on June 5th.  Mars and Mercury undergo a very close conjunction on June 18th.

Jupiter reaches opposition on June 10th.  At that time, it shines at magnitude -2.5, subtends 46.0 arc seconds, has a declination of -22 degrees, and is 36 light minutes from the Earth.  The waxing gibbous Moon passes two degrees north of Jupiter on June 16th.  An article on observing Jupiter appears on pages 52 and 53 of the May 2019 issue of Sky & Telescope.  Browse http://www.skyandtel...watching-tools/ or http://www.projectpl...om/jeve_grs.htm in order to determine transit times of Jupiter’s central meridian by the Great Red Spot.  GRS transit times are also available on page 50 of the June 2019 issue of Sky & Telescope.  Javascript Jupiter at http://www.shallowsky.com/jupiter/ shows Galilean satellite events.  Data on the Galilean satellite events can also be found on page 51 of the June 2019 issue of Sky & Telescope and at https://www.projectp.../jevent.htm#jun and http://www.skyandtel...atching-tools/ 

Saturn rises at about 11:00 p.m. local daylight time on June 1st.  The planet shines at magnitude +0.2 and subtends 18.2 arc seconds at its equator, while its rings span 41 arc seconds and are inclined 24 degrees.  The waxing gibbous Moon passes less than one degree south of Saturn, with an occultation occurring in some parts of the world, on June 19th.  Eighth-magnitude Titan passes north of Saturn on the mornings of June 13th and June 29th and south of the planet on the mornings of June 5th and June 21st.  For information on Saturn’s satellites, browse http://www.skyandtel...atching-tools/ 

By the end of the month, Uranus rises at about 2:00 a.m. local daylight time.  The ice giant is situated in southern Aries, some ten degrees south of the first-magnitude star Hamal (Alpha Arietis) and 2.4 degrees south of the sixth-magnitude star 19 Arietis.  The waxing gibbous Moon passes five degrees north of Uranus on June 27th.  Visit http://www.bluewater...anus_2019_1.pdf and http://www.nakedeyep...htm#finderchart for finder charts. 

Neptune rises shortly after 1:00 a.m. local daylight time by mid-June.  The eighth planet lies 1.2 degree east-northeast of the fourth-magnitude star Phi Aquarii on June 1st.  Neptune reaches its first stationary point on June 22nd, when it will be less than 1.5 degrees northeast of Phi Aquarii and less than 0.5 degree south of the sixth-magnitude star 96 Aquarii. 
The waning gibbous Moon passes four degrees south of Neptune on June 24.  Browse https://s22380.pcdn....p-2019-2020.pdf and http://www.nakedeyep...htm#finderchart for finder charts.

Finder charts for Uranus and Neptune are available at https://s22380.pcdn....p-2019-2020.pdf

Pluto resides in northeastern Sagittarius.  The waxing gibbous Moon passes 0.1 degree south of Pluto, with an occultation occurring in some parts of the world, on June 19th.  Finder charts can be found at http://www.bluewater...9/Pluto2019.jpg and on pages 48 and 49 of the July 2019 issue of Sky & Telescope and page 243 of the RASC Observer’s Handbook 2019.

For more on the planets and how to locate them, browse 
http://www.nakedeyeplanets.com/

Comet C/2018 N2 (ASASSN) travels northeastward through northeastward through northeastern Cetus during June. The faint comet lies about 1.5 degrees to the east of the fourth-magnitude star Xi Ceti on June 30th.  Visit http://cometchasing.skyhound.com/ and http://www.aerith.ne...t/future-n.html for information on comets visible this month. 

Shining at ninth magnitude, asteroid 2 Pallas glides southeastward through eastern Coma Berenices this month.  It lies about two degrees to the west of the sixth-magnitude star 2 Boötes on June 21st.  The main belt asteroid passes very close to similarly bright stars on June 12th and June 26th.  Asteroids brighter than magnitude +11.0 that reach opposition this month include 410 Chloris (magnitude +10.3) on June 14th, 22 Kalliope (magnitude +10.8) on June 15th, and 914 Palisana (magnitude +10.8) on June 28th.  Information on asteroid occultations taking place this month is available at http://www.asteroido.../2019_06_si.htm

For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/

A wealth of current information on solar system celestial bodies is posted at http://www.curtrenz.com/astronomy.html and http://nineplanets.org/

Various events taking place within our solar system are discussed at http://www.bluewater...ed-4/index.html

Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtel...ky-at-a-glance/

Free star maps for May can be downloaded at http://www.skymaps.com/downloads.html and https://www.telescop...thly-Star-Chart

Data on current supernovae can be found at http://www.rochester...y.org/snimages/

Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and http://www.cambridge..._april-june.htm

Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.astro-tom...charts/map1.pdf and http://www.saguaroas...k110BestNGC.pdf respectively.

Information pertaining to observing some of the more prominent Messier galaxies can be found at http://www.cloudynig...ur-astronomers/

Stellarium and Cartes du Ciel are two excellent freeware planetarium programs that are available at http://stellarium.org/ and https://www.ap-i.net/skychart/en/start

Deep-sky object list generators can be found at http://www.virtualcolony.com/sac/ and http://tonightssky.com/MainPage.php and https://dso-browser.com/

Freeware sky atlases can be downloaded at http://www.deepskywa...-atlas-full.pdf and http://astro.mxd120....ee-star-atlases

Forty binary and multiple stars for June:
Struve 1812, Kappa Bootis, Otto Struve 279, Iota Bootis, Struve 1825, Struve 1835, Pi Bootis, Epsilon Bootis, Struve 1889, 39 Bootis, Xi Bootis, Struve 1910, Delta Bootis, Mu Bootis (Bootes);
Struve 1803 (Canes Venatici);
Struve 1932, Struve 1964, Zeta Coronae Borealis, Struve 1973, Otto Struve 302 (Corona Borealis);
Struve 1927, Struve 1984, Struve 2054, Eta Draconis, 17-16 Draconis, 17 Draconis (Draco);
54 Hydrae (Hydra);
Struve 1919, 5 Serpentis, 6 Serpentis, Struve 1950, Delta Serpentis, Otto Struve 300, Beta Serpentis, Struve 1985 (Serpens Caput);
Struve 1831 (Ursa Major);
Pi-1 Ursae Minoris (Ursa Minor);
Struve 1802, Struve 1833, Phi Virginis (Virgo)

Notable carbon star for June: V Coronae Borealis

Fifty deep-sky objects for June:
NGC 5466, NGC 5676, NGC 5689 (Bootes);
M102 (NGC 5866), NGC 5678, NGC 5879, NGC 5905, NGC 5907, NGC 5908, NGC 5949, NGC 5963, NGC 5965, NGC 5982, NGC 5985, NGC 6015 (Draco);
NGC 5694 (Hydra);
NGC 5728, NGC 5791, NGC 5796, NGC 5812, NGC 5861, NGC 5878, NGC 5897 (Libra);
M5, NGC 5921, NGC 5957, NGC 5962, NGC 5970, NGC 5984 (Serpens Caput); M101, NGC 5473, NGC 5474, NGC 5485, NGC 5585, NGC 5631 (Ursa Major);
NGC 5566, NGC 5634, NGC 5701, NGC 5713, NGC 5746, NGC 5750, NGC 5775, NGC 5806, NGC 5813, NGC 5831, NGC 5838, NGC 5846, NGC 5850, NGC 5854, NGC 5864 (Virgo)

Top ten deep-sky objects for June: M5, M101, M102, NGC 5566, NGC 5585, NGC 5689, NGC 5746, NGC 5813, NGC 5838, NGC 5907

Top five deep-sky binocular objects for June: M5, M101, M102, NGC 5466, NGC 5907

Challenge deep-sky object for June: Abell 2065


The objects listed above are located between 14:00 and 16:00 hours of right ascension.




May Celestial Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)

5/2   Saturn (magnitude +0.5) is 2.7 degrees west of Pluto (magnitude +14.3) at 5:00; the Moon is 4.0 degrees north of Venus at 12:00; the Moon is 0.2 degree north of asteroid 4 Vesta, with an occultation occurring in southern Europe, northwestern Africa, the Cape Verde Islands, the Azores, northern South America, and the Galapagos Islands, at 13:00; the Moon is 3.4 degrees south-southeast of Venus at 15:00

5/3   The Moon is 2.7 degrees south-southeast of Mercury at 10:00; Mars and Saturn are at heliocentric opposition (longitudes 105.2 degrees and 285.2 degrees) at 14:00

5/4   The Moon is 4.4 degrees south-southeast of Uranus at 3:00; New Moon (lunation 1192) occurs at 22:46

5/5   Today is May Day or Beltane, a cross-quarter day; the peak of the Eta Aquarid meteor shower (20 per hour for northern hemisphere observers) occurs at 13:00

5/6   The Moon is 7.9 degrees south-southeast of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 5:00; the Moon is 2.2 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 22:00

5/8   The Moon is 3.2 degrees south-southeast of Mars at 1:00; Mercury (magnitude -0.8) is 1.3 degrees south-southeast of Uranus (magnitude +5.9) at 16:00

5/9   The Moon is at descending node (longitude 109.3 degrees) at 19:00

5/10 The Moon is 6.3 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 3:00; Venus is at its southernmost latitude from the ecliptic plane (-3.4 degrees) at 6:00

5/11 The Moon lies within the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 2:00; the Lunar X (also known as the Werner or Purbach Cross), an X-shaped clair-obscure illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to be fully formed at 16:25; asteroid 8 Flora (magnitude +9.8) is at opposition at 23:00

5/12 First Quarter Moon occurs at 1:12; the Moon is 2.9 degrees north-northeast of the first-magnitude star Regulus (Alpha Leonis) at 17:00

5/13 The Moon is at perigee, subtending 32' 23'' from a distance of 369,009 kilometers (229,291 miles), at 21:53

5/14 The equation of time is at a maximum of 3.65 minutes at 9:00; asteroid 11 Parthenope (magnitude +9.5) is at opposition at 10:00; the Sun enters Taurus (longitude 53.47 degrees on the ecliptic) at 13:00

5/16 The Moon is 7.1 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 12:00; Mars is at its northernmost declination (24.6 degrees) at 22:00

5/18 Venus (magnitude -3.9) is 1.1 degrees south-southeast of Uranus (magnitude +5.9) at 17:00; Full Moon, known as the Milk or Planting Moon, occurs at 21:11

5/19 Mercury is at the ascending node through the ecliptic plane at 15:00; Mars is 0.2 degree north of the bright open cluster M35 in Gemini at 16:00; the Moon is 1.2 degrees south of the dwarf planet/asteroid 1 Ceres, with an occultation occurring in parts of Antarctica, at 18:00; the Moon is 7.8 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 21:00

5/20 Asteroid 20 Massalia (magnitude +9.8) is at opposition at 13:00; the Moon is 1.7 degrees north-northeast of Jupiter at 18:00

5/21 The Sun’s longitude is 60 degrees at 8:00; Mercury is in superior conjunction (a distance of 1.322 a.u. from Earth and a latitude of 1.42 degrees) with the Sun at 13:00; Mercury is 3.7 degrees south-southeast of M45 at 15:00

5/22 The Moon is at the descending node (longitude 288.5 degrees) at 19:00; the Moon, Saturn, and Pluto lie within a circle with a diameter of 2.94 degrees at 23:00; the Moon is 0.5 degree south of Saturn, with an occultation occurring in southern New Zealand, most of Australia, the Kerguelen Islands, parts of eastern Antarctica, and the southern tip of Africa, at 22:00

5/23 The Moon is 0.1 degree south of Pluto, with an occultation occurring in southern and eastern Africa and central South America, at 4:00

5/24 Mercury is at perihelion (0.3075 a.u. from the Sun) at 7:00

5/25 Mercury is 6.5 degrees north-northwest of Aldebaran at 18:00

5/26 The Moon is at apogee, subtending 29' 34'' from a distance of 404,137 kilometers (251,119 miles), at 13:27; Last Quarter Moon occurs at 16:34

5/27 The Curtiss Cross, an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart, is predicted to be visible at 19:32; the Moon is 3.5 degrees south-southeast of Neptune at 20:00

5/28 The dwarf planet/asteroid 1 Ceres (magnitude +7.0) is at opposition at 23:00

5/30 The Moon is 0.6 degree north of asteroid 4 Vesta, with an occultation occurring in northwestern North America, the Aleutian Islands, northwestern Micronesia, eastern Asia, and parts of Indonesia, at 22:00

5/31 The Moon is 4.5 degrees south-southeast of Uranus at 14:00

*Nicolas Lacaille (1713-1762), Otto Wilhelm Struve (1819-1905), Joseph Lockyer (1836-1920), Williamina Fleming (1857-1911), and Frank Drake (1930) were born this month.

*The first recorded perihelion passage of Comet Halley (1P/Halley) occurred on May 25, 240 BC. 

*Thales of Miletus accurately predicted a solar eclipse on May 28, 585 BC.

*The German astronomers Gottfried and Maria Magarethe Kirch discovered the bright globular cluster M5 on May 5, 1702.

*On May 1, 1759, the English amateur astronomers John Bevis and Nicholas Munckley observed Comet Halley on its first predicted return. 
*The French astronomer Charles Messier discovered the globular cluster M3 on May 3, 1764 and the globular cluster M10 on May 29, 1764. 

*The Italian astronomer Annibale de Gasparis discovered asteroid 11 Parthenope on May 11, 1850. 

*Asteroid 14 Irene was discovered on May 19, 1851 by the English astronomer John Russell Hind. 

*The German astronomer Robert Luther discovered asteroid 26 Proserpina on May 6, 1853. 

*The Australian astronomer John Tebbutt discovered the Great Comet of 1861 on May 13. 

*The English astronomer Norman Pogson discovered asteroid 80 Sappho on May 2, 1864. 
Norman Pogson discovered asteroid 87 Sylvia on May 16, 1866. 

*The 40-inch Clark refractor at the Yerkes Observatory saw first light on May 21, 1897. 

*The Griffith Observatory opened to the public on May 14, 1935. 

*Nereid, Neptune’s third-largest satellite, was discovered on May 1, 1949 by the Dutch-American astronomer Gerard Kuiper.

The broad peak of the Eta Aquarid meteor shower is not adversely affected by moonlight this year.  Southern hemisphere observers are favored.  Eta Aquarid meteors are debris from the famous periodic comet 1P/Halley.  The radiant is located close to the Water Jug asterism in Aquarius.  See  https:https://www.amsmeteo.../#eta Aquariids and page 48 of the May 2019 issue of Sky & Telescope for additional information on the Eta Aquarids.

Information on the few remaining Iridium satellite flares and passes of the ISS, the Tiangong-2, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/
The Moon is 25.5 days old, is illuminated 16.2%, subtends 29.3 arc minutes, and is located in Aquarius on May 1st at 0:00 UT.  The Moon is at its greatest northern declination on May 9th (+22.2 degrees).  The Moon is at its greatest its greatest southern declination on May 22nd (-22.3 degrees).  Longitudinal libration is at maximum (+5.0 degrees) on May 19th and at minimum (-5.0 degrees) on May 6th.  Latitudinal libration is at maximum (+6.6 degrees) on May 3rd and again (+6.7 degrees) on May 30th and at minimum (-6.6 degrees) on May 16th.  The Moon is at apogee (distance 63.36 Earth-radii) on May 26th and at perigee (distance 57.86 Earth-radii) on May 13th.  New Moon occurs on May 4th.  The 39%-illuminated Moon transits M44 from 2:00 to 4:00 UT on May 11th.  See https://occultations.org/campaigns/ for further information on this event.  The Moon occults 4 Vesta on May 2nd and May 30th, 1 Ceres on May 19th, Saturn on May 22nd, and Pluto on May 23rd from certain parts of the world.  Consult http://www.lunar-occ...ota/iotandx.htm for more on lunar occultations.  Visit http://saberdoesthes...does-the-stars/ for tips on spotting extreme crescent Moons.  Click on http://www.calendar-...lendar/2019/may for a lunar phase calendar.  Times and dates for the lunar light rays predicted to occur this month are available at http://www.lunar-occ...o/rays/rays.htm
The Sun is located in Aries on May 1st.  It enters Taurus on May 14th.

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on May 1st:
Mercury (magnitude -0.4, 5.8", 75% illuminated, 1.15 a.u., Pisces),
Venus (magnitude -3.8, 11.5", 88% illuminated, 1.45 a.u., Pisces),
Mars (magnitude +1.6, 4.2", 96% illuminated, 2.24 a.u., Taurus),
Jupiter (magnitude -2.5, 43.5", 100% illuminated, 4.54 a.u., Ophiuchus),
Saturn (magnitude +0.5, 17.2", 100% illuminated, 9.67 a.u., Sagittarius),
Uranus on May 16th (magnitude +5.9, 3.4", 100% illuminated, 20.79 a.u., Aires), Neptune on May 16th (magnitude +7.9, 2.3", 100% illuminated, 30.33 a.u., Aquarius), and Pluto on May 16th (magnitude +14.2, 0.1", 100% illuminated, 32.72 a.u., Sagittarius). 

In the evening, Mercury is in the northwest and Mars is in the west. 
Jupiter is located in the southeast at midnight. 
Mercury, Venus, and Uranus can be seen in the east, Saturn in the south, Jupiter in the southwest, and Neptune in the southeast at dawn.

Mercury can be seen extremely low in the east during early part of the month.  A very slender waning crescent Moon passes three degrees to the south of Mercury on May 3rd.  Mercury is in superior conjunction on May 21st.  As May ends, the speediest planet enters the evening sky and can be seen to the lower right of Mars in the west-northwest 30 minutes after the Sun sets.   Mercury shines brightly at magnitude -1.2 at that time.

During May, Venus rises about an hour before the Sun and shines at its minimum brightness of magnitude -3.8.  A thin waning crescent Moon passes four degrees south of the planet on May 2nd.  Venus is at its greatest heliocentric latitude south on May 10th.  Venus lies 1.2 degrees south of Uranus on May 18th.

Mars lies between the horns of Taurus, Beta and Zeta Tauri, on May 6th.  A waxing crescent Moon passes three degrees south of Mars on May 7th.  The Red Planet departs Taurus and enters Gemini by the middle of the month.  Mars is at its northernmost declination (24.6 degrees) on May 16th.  Mars shrinks to 3.9 arc seconds and shines at only magnitude +1.8 by the end of May.

Jupiter increases in apparent size from 43.5 to 45.8 arc seconds this month.  The waning gibbous Moon passes less than two degrees to the north of Jupiter on May 20th.  The orbital plane of the Galilean satellites is currently inclined three degrees to our line of sight.  A shadow transit by Ganymede begins at 3:42 a.m. EDT on the morning of May 7th.  On the morning of May 18th, Ganymede reappears from occultation at 2:16 a.m. EDT.  Io’s shadow begins to transit the planet at 3:44 a.m. EDT followed by Io itself at 4:17 a.m. EDT.  Ganymede begins to disappear into eclipse to the west of Jupiter at 1:41 a.m. EDT on the morning of May 25th, an event that will take 14 minutes to transpire.  Articles on observing Jupiter and the Great Red Spot (GRS) appear on pages 52 and 53 respectively of the May 2019 issue of Sky & Telescope.  Browse http://www.skyandtel...watching-tools/ or http://www.projectpl...om/jeve_grs.htm in order to determine transit times of Jupiter’s central meridian by the GRS.  GRS transit information also appears on pages 50 and 51 of the May 2019 issue of Sky & Telescope.  Data on the Galilean satellite events is available on page 51 of the May 2019 issue of Sky & Telescope and online at http://www.skyandtel...watching-tools/ and http://www.projectpl...om/jevent.htm

Saturn retrogrades through eastern Sagittarius this month.  It shines at magnitude +0.4 and has an apparent equatorial diameter of almost 18 arc seconds at mid-month.  Saturn’s rings subtend more than 40 arc seconds and are inclined by nearly 24 degrees at that time.  In late May, Saturn nears the meridian as morning twilight begins.  The waning gibbous Moon passes one half degree south of Saturn on May 22nd.  Eighth-magnitude Titan, Saturn’s brightest satellite, is located south of the planet on May 4th and May 20th and north of it on May 12th and May 28th.  Saturn’s odd satellite Iapetus shines faintly at eleventh magnitude when it passes north of Saturn on May 18th and May 19th.  For further information on Saturn’s satellites, browse http://www.skyandtel...atching-tools/

Uranus can be seen once again during morning twilight during the second half of May.  Venus passes 1.2 degrees due south of Uranus on May 18th.  On May 31st, the waning crescent Moon passes 4.5 degrees south-southeast of Uranus.  The two celestial objects rise more than an hour before the Sun on that date.

Neptune is located 1.2 degrees east-northeast of the fourth-magnitude star Phi Aquarii in eastern Aquarius this month.  The waning crescent Moon passes 3.5 degrees south-southeast of Neptune on May 27th.  Neptune reaches an altitude of nearly 20 degrees in east-southeast as morning twilight begins on the final day of the month.

Pluto lies in northeastern Sagittarius and transits the meridian before dawn.

Comet C/2017 M4 (ATLAS) passes west-southwestward through Scorpius and into Lupus in May.  This faint comet is located five degrees west of the third-magnitude star Mu1 Scorpii on May 1st.  It passes a bit more than one degree north of the ninth-magnitude globular cluster NGC 6139 on May 3rd and 1.3 degrees south of the third-magnitude star Eta Lupi on May 13th.  Visit http://cometchasing.skyhound.com/ and http://www.aerith.ne...ly/current.html for information on comets visible this month.  

The dwarf planet/asteroid 1 Ceres (magnitude +7.0) reaches opposition in western Ophiuchus on May 28th.  Ceres retrogrades into Scorpius shortly thereafter.  A finder chart can be found on page 48 of the May 2019 issue of Sky & Telescope.  With a diameter of 940 kilometers (585 miles), Ceres is the largest object in the main asteroid belt and is the only asteroid to be differentiated, i.e., to have layers.  Other asteroids brighter than magnitude +11.0 that reach opposition this month include 8 Flora (magnitude +9.8) on May 12th, 11 Parthenope (magnitude +9.5) on May 14th, 68 Leto (magnitude +10.7) on May 14th, 20 Massalia (magnitude +9.8) on May 20th, and 32 Pomona (magnitude +10.5) on May 27th.  Information on asteroid occultations taking place this month is available at http://www.asteroido.../2019_05_si.htm

For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/

A wealth of current information on solar system celestial bodies is posted at http://www.curtrenz.com/astronomy.html and http://nineplanets.org/

Various events taking place within our solar system are discussed at http://www.bluewater...ed-4/index.html

Information on the celestial events transpiring each week can be found at http://astronomy.com/skythisweek and http://www.skyandtel...ky-at-a-glance/

Free star maps for May can be downloaded at http://www.skymaps.com/downloads.html and https://www.telescop...thly-Star-Chart

Data on current supernovae can be found at http://www.rochester...y.org/snimages/

Finder charts for the Messier objects and other deep-sky objects are posted at https://freestarcharts.com/messier and https://freestarcharts.com/ngc-ic and http://www.cambridge..._april-june.htm

Telrad finder charts for the Messier Catalog and the SAC’s 110 Best of the NGC are posted at http://www.astro-tom...charts/map1.pdf and http://www.saguaroas...k110BestNGC.pdf respectively.

Information pertaining to observing some of the more prominent Messier galaxies can be found at http://www.cloudynig...ur-astronomers/

Stellarium and Cartes du Ciel are two excellent freeware planetarium programs that are available at http://stellarium.org/ and https://www.ap-i.net/skychart/en/start

Deep-sky object list generators can be found at http://www.virtualcolony.com/sac/ and http://tonightssky.com/MainPage.php and https://dso-browser.com/

Freeware sky atlases can be downloaded at http://www.deepskywa...-atlas-full.pdf and http://astro.mxd120....ee-star-atlases

Eighty binary and multiple stars for May:
1 Bootis, Struve 1782, Tau Bootis, Struve 1785, Struve 1812 (Bootes);
2 Canum Venaticorum, Struve 1624, Struve 1632, Struve 1642, Struve 1645, 7 Canum Venaticorum, Alpha Canum Venaticorum (Cor Caroli), h2639, Struve 1723, 17 Canum Venaticorum, Otto Struve 261, Struve 1730, Struve 1555, h1234, 25 Canum Venaticorum, Struve 1769, Struve 1783, h1244 (Canes Venatici);
2 Comae Berenices, Struve 1615, Otto Struve 245, Struve 1633, 12 Comae Berenices, Struve 1639, 24 Comae Berenices, Otto Struve 253, Struve 1678, 30 Comae Berenices, Struve 1684, Struve 1685, 35 Comae Berenices, Burnham 112, h220, Struve 1722, Beta Comae Berenices, Burnham 800, Otto Struve 266, Struve 1748 (Coma Berenices);
h4481, h4489, Struve 1604, Delta Corvi, Burnham 28, h1218, Struve 1669 (Corvus);
H N 69, h4556 (Hydra); Otto Struve 244, Struve 1600, Struve 1695, Zeta Ursae Majoris (Mizar), Struve 1770, Struve 1795, Struve 1831 (Ursa Major);
Struve 1616, Struve 1627, 17 Virginis, Struve 1648, Struve 1658, Struve 1677, Struve 1682, Struve 1689, Struve 1690, 44 Virginis, Struve 1719, Theta Virginis, 54 Virginis, Struve 1738, Struve 1740, Struve 1751, 81 Virginis, Struve 1764, Struve 1775, 84 Virginis, Struve 1788 (Virgo)

Notable carbon star for May: SS Virginis

One hundred and sixty-five deep-sky objects for May:
NGC 5248 (Bootes);
M3, M51, M63, M94, M106, NGC 4111, NGC 4138, NGC 4143, NGC 4151, NGC 4214, NGC 4217, NGC 4244, NGC 4346, NGC 4369, NGC 4449, NGC 4485, NGC 4490, NGC 4618, NGC 4631, NGC 4656, NGC 4868, NGC 5005, NGC 5033, NGC 5297, NGC 5353, NGC 5354, Up 1 (Canes Venatici);
Mel 111, M53, M64, M85, M88, M91, M98, M99, M100, NGC 4064, NGC 4150, NGC 4203, NGC 4212, NGC 4251, NGC 4274, NGC 4278, NGC 4293, NGC 4298, NGC 4302, NGC 4314, NGC 4350, NGC 4414, NGC 4419, NGC 4448, NGC 4450, NGC 4459, NGC 4473, NGC 4474, NGC 4494, NGC 4559, NGC 4565, NGC 4651, NGC 4689, NGC 4710, NGC 4725, NGC 4874, NGC 5053 (Coma Berenices);
NGC 4027, NGC 4038-9, NGC 4361 (Corvus);
M68, M83, NGC 4105, NGC 4106, NGC 5061, NGC 5101, NGC 5135 (Hydra);
M40, NGC 4036, NGC 4041, NGC 4051, NGC 4062, NGC 4085, NGC 4088, NGC 4096, NGC 4100, NGC 4144, NGC 4157, NGC 4605, NGC 5308, NGC 5322 (Ursa Major);
M49, M58, M59, M60, M61, M84, M86, M87, M89, M90, M104, NGC 4030, NGC 4073, NGC 4168, NGC 4179, NGC 4206, NGC 4215, NGC 4216, NGC 4224, NGC 4235, NGC 4260, NGC 4261, NGC 4267, NGC 4281, NGC 4339, NGC 4343, NGC 4365, NGC 4371, NGC 4378, NGC 4380, NGC 4387, NGC 4388, NGC 4402, NGC 4429, NGC 4435, NGC 4438, NGC 4517, NGC 4526, NGC 4535, NGC 4536, NGC 4546, NGC 4550, NGC 4551, NGC 4567, NGC 4568, NGC 4570, NGC 4593, NGC 4596, NGC 4636, NGC 4638, NGC 4639, NGC 4643, NGC 4654, NGC 4666, NGC 4697, NGC 4698, NGC 4699, NGC 4753, NGC 4754, NGC 4760, NGC 4762, NGC 4866, NGC 4900, NGC 4958, NGC 5044, NGC 5054, NGC 5068, NGC 5077, NGC 5084, NGC 5087, NGC 5147, NGC 5170, NGC 5247, NGC 5363, NGC 5364 (Virgo)

Top ten deep-sky objects for May: M3, M51, M63, M64, M83, M87, M104, M106, NGC 4449, NGC 4565

Top ten deep-sky binocular objects for May: M3, M51, M63, M64, M84, M86, M87, M104, M106, Mel 111

Challenge deep-sky object for May: 3C 273 (Virgo)

The objects listed above are located between 12:00 and 14:00 hours of right ascension.







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