January Celestial Calendar by Dave Mitsky
All times are UT (subtract five hours, and one calendar day when appropriate, for EST)
1/2 The Earth is at perihelion (147,093,463 kilometers or 91,399,454 miles distant from the Sun) at 13:51
1/3 The peak of the Quadrantid meteor shower (40 to 120 or more per hour) is predicted to occur at 14:30; the Moon is 4.5 degrees north of the first-magnitude star Regulus (Alpha Leonis) at 2:00
1/4 The latest sunrise of the year at latitude 40 degrees north occurs today
1/5 Mercury is at its southernmost latitude from the ecliptic plane (-7.0 degrees) at 9:00
1/6 Last Quarter Moon occurs at 9:37
1/7 The latest onset of morning twilight of the year at latitude 40 degrees north occurs today; the Moon is 6.4 degrees north-northeast of the first-magnitude star Spica (Alpha Virginis) at 0:00; the Curtiss Cross, an X-shaped clair-obscure illumination effect located between the craters Parry and Gambart, is predicted to begin at 7:08
1/9 The Moon is at perigee, subtending 32’ 32" from a distance of 367,389 kilometers (228,284 miles), at 15:37
1/10 Mercury (magnitude -0.9) is 1.6 degrees southeast of Saturn (magnitude +0.6) at 5:00; the Moon is 5.4 degrees north-northeast of the first-magnitude star Antares (Alpha Scorpii) at 6:00; Mercury, Jupiter, and Saturn lie within a circle with a diameter of 2.4 degrees at 19:00; the Moon is at the descending node (longitude 259.7 degrees) at 20:00
1/11 Mercury (magnitude -0.9) is 1.4 degrees southeast of Jupiter (magnitude -1.9) at 19:00; the Moon is 1.5 degrees south of Venus at 21:00
1/12 Venus is at its southernmost declination (-23.2 degrees) at 6:00
1/13 New Moon (lunation 1201) occurs at 12:13; the Moon is 3.2 degrees southeast of Saturn at 23:00
1/14 The Moon, Mercury and Saturn lie within a circle with a diameter of 6.0 degrees at 0:00; the Moon, Jupiter, and Saturn lie within a circle with a diameter of 3.8 degrees at 0:00; the Moon is 3.3 degrees southeast of Jupiter at 3:00; the Moon, Mercury and Jupiter lie within a circle with a diameter of 4.0 degrees at 5:00; Pluto is in conjunction with the Sun (35.18 astronomical units from the Earth, latitude -1.2 degrees) at 7:00; the Moon is 2.3 degrees southeast of Mercury at 10:00; Uranus is stationary, with prograde (eastward) motion to commence, at 11:00
1/16 Venus is at the descending node through the ecliptic plane at 12:00
1/17 The Moon is 4.1 degrees southeast of Neptune at 10:00
1/19 The Sun enters Capricornus (ecliptic longitude 299.7 degrees) at 15:00; the Sun's longitude is 300 degrees at 21:00
1/20 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 at 18:31; Mars (magnitude +0.2) is 1.6 degrees north-northwest of Uranus (magnitude +5.8) at 20:00; First Quarter Moon occurs at 21:02
1/21 The Moon is 3.1 degrees southeast of Uranus at 10:00; the Moon, Mars, and Uranus lie within a circle with a diameter of 4.6 degrees at 10:00; the Moon is 4.7 degrees southeast of Mars at 11:00; the Moon is at apogee, subtending 29' 33" from a distance of 404,360 kilometers (251,258 miles), at 13:11; asteroid 15 Eunomia (magnitude +8.4) is at opposition in Cancer at 19:00
1/22 Mars is 1.7 degrees north of Uranus at 0:00
1/23 The Moon is 5.7 degrees southeast of the bright open cluster M45 (the Pleiades or Subaru) in Taurus at 10:00; asteroid 4 Vesta (magnitude +7.1) is stationary in Leo at 22:00
1/24 Mercury is at greatest eastern elongation (18.6 degrees) at 2:00; Saturn is in conjunction with the Sun at 3:00; the Moon is 4.0 degrees north of Aldebaran at 4:00; Mercury is at the ascending node through the plane of the ecliptic at 10:00; asteroid 14 Irene (magnitude +9.3) is at opposition in Cancer at 17:00; the Moon is at the descending node (longitude 79.1 degrees) at 22:00
1/26 The Moon is 0.3 degrees north-northeast of the bright open cluster M35 in Gemini at 0:00; Uranus is at eastern quadrature (90 degrees from the Sun) at 13:00
1/27 The Moon is 7.4 degrees south of the first-magnitude star Castor (Alpha Geminorum) at 11:00; the Moon is 3.8 degrees south of the first-magnitude star Pollux (Beta Geminorum) at 16:00
1/28 The Moon is 2.6 degrees north-northeast of the bright open cluster M44 (the Beehive Cluster or Praesepe) in Cancer at 17:00; Full Moon (known as the Ice Moon, the Moon after Yule, the Old Moon, and the Wolf Moon) occurs at 19:16
1/29 Jupiter is in conjunction with the Sun (6.071 astronomical units from the Earth, latitude -0.63 degrees) at 2:00; Mercury is at perihelion (0.3075 astronomical units from the Sun) at 2:00
1/30 Mercury is stationary, with retrograde (western) motion to commence, at 2:00; the Moon is 4.4 degrees north-northeast of Regulus at 9:00
Johannes Hevelius (1611-1687), Ernst Abbe (1840-1905), George Van Biesbroeck (1880-1974), Luboš Kohoutek (1935), and Stephen Hawking (1942-2018) 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 9:30 a.m. EST (14:30 UT) on January 3rd. 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. Unfortunately, a waning gibbous Moon will 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 https://earthsky.org/?p=155137 and https://amsmeteors.o...hower-calendar/ for more on the Quadrantids. The major meteor showers occurring this year are discussed at https://www.skyandte...howers-in-2021/
Information on Iridium flares and passes of the ISS, the X-37B, the HST, Starlink, and other satellites can be found at https://www.heavens-above.com/
The Moon is 17.2 days old, is illuminated 97.0%, subtends 31.1 arc minutes, and is located in Gemini on January 1st at 0:00 UT. It attains its greatest northern declination for the month on January 27th (+24.8 degrees) and its greatest southern declination (-24.8 degrees) on January 12th. Longitudinal libration is at a maximum of +5.4 degrees on December 16th. It’s at a minimum of -5.2 degrees on January 1st and -5.3 degrees on January 28th. Latitudinal libration is at a maximum of +6.7 degrees on January 17th and a minimum of -6.7 degrees on January 4th. Favorable librations for the following lunar features occur on the indicated dates: Crater Inghirami on January 3rd, Crater Kircher on January 8th, Crater Bel'Kovich on January 19th, and Crater Pingre on January 31st. The Moon is at perigee (distance 57.60 Earth-radii) on January 9th and at apogee (distance 63.40 Earth-radii) on January 21st. The Maginus Lunar Sunrise Crater Light Ray is predicted to occur at 12:41 UT on January 21st. 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 https://curtrenz.com/moon.html for Full Moon and other lunar data. Consult http://time.unitariu...moon/where.html for current information on the Moon. Visit http://www.ap-i.net/avl/en/start to download the free Virtual Moon Atlas. Browse https://skyandtelesc...ads/MoonMap.pdf for a lunar map. See https://svs.gsfc.nasa.gov/4874 for a lunar phase and libration calculator and https://quickmap.lro...2vIBvAXwF1SizSg for the Lunar Reconnaissance Orbiter Camera (LROC) Quickmap. Click on https://www.calendar...r/2021/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 Sagittarius on January 1st. It enters Capricornus on January 19th.
Data (magnitude, apparent size, illumination, and distance from the Earth in astronomical units) for the planets and Pluto on January 1st: Mercury (-1.0, 4.8", 98%, 1.39 a.u., Sagittarius), Venus (-3.9, 10.7", 94%, 1.56 a.u., Ophiuchus), Mars (-0.2, 10.4", 89%, 0.90 a.u., Pisces), Jupiter (-2.0, 32.9", 100%, 5.99 a.u., Capricornus), Saturn (+0.6, 15.2", 100%, 10.90 a.u., Capricornus), Uranus (+5.7, 3.6", 100%, 19.57 a.u. on January 16th, Aries), Neptune (+7.9, 2.2", 100%, 30.51 a.u. on January 16th, Aquarius), Pluto (+14.4, 0.1", 100%, 35.18 a.u. on January 16th, Sagittarius).
During the evening, Mars and Uranus in the south, Mercury and Neptune lie in the southwest, and Jupiter and Saturn in the west. At midnight, Mars and Uranus are in the west. Venus can be seen in the southeast in the morning.
Mercury, Jupiter, and Saturn lie within a circle with a diameter of 2.4 degrees on January 10th. On the evening of January 13th (January 14th UT), the Moon, Mercury and Saturn lie within a circle with a diameter of 6.0 degrees, the Moon, Jupiter, and Saturn lie within a circle with a diameter of 3.8 degrees, and the Moon, Mercury and Jupiter lie within a circle with a diameter of 4.0 degrees. The Moon, Mars, and Uranus lie within a circle with a diameter of 4.6 degrees on January 21st.
Mercury is at its greatest heliocentric latitude south on January 5th. It returns to the evening sky at twilight after January 8th and is 1.6 degrees southeast of Saturn on January 10th. Mercury is 1.4 degrees southeast of Jupiter on January 11th. The speediest planet is located 2.3 degrees north of the young Moon on January 14th. Mercury is at greatest eastern elongation, the second best of 2021, on January 23rd (January 24th UT). Mercury sets about 90 minutes after the Sun and shines at magnitude -0.6 on that date. Mercury reaches perihelion on January 29th. On that date, it is also stationary and subsequently begins to retrograde.
Venus grows increasingly more difficult to observe at January progresses. It rises more than an hour before sunrise on January 1st but only about 30 minutes before the Sun rises as January ends. Venus lies between M8 (the Lagoon Nebula) and M20 (the Trifid Nebula) on the morning of January 9th. A slender waning crescent Moon passes 1.5 degrees south of the brightest planet on January 11th. Venus is at its southernmost declination on January 12th. The prominent globular cluster M22 lies 46 arc minutes south of Venus on January 15th.
Earth is 0.9833 a.u. distant from the Sun at perihelion on January 2nd. 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 5th and about 2.7% closer to the Sun than on average.
Mars begins the month with a brightness of magnitude -0.2 and an apparent diameter of 10.4 arc seconds. It is illuminated 89% for the entire month. As January begins, Mars is near the sixth-magnitude star Pi Piscium. The Red Planet departs Pisces and enters Aries on January 5th. Mars passes within six degrees of the fourth-magnitude star Mesarthim (Gamma Arietis) on January 13th. Mars and Uranus are less than two degrees apart from January 18th to January 22nd. On January 21st, Mars is located 1.7 degrees due north of Uranus. The waxing gibbous Moon passes 4.7 degrees southeast of Mars on that date. At month's end, Mars shines at only magnitude +0.4 and subtends just 7.9 arc seconds.
Jupiter and Saturn are steadily growing apart since the historic conjunction on December 21st and are 1.3 degrees apart on January 1st. By January 7th, the two gas giant planets are separated by two degrees. The young crescent Moon passes 3.3 degrees southeast of Jupiter on January 14th. Jupiter is in conjunction with the Sun on January 29th.
Saturn can be seen during evening twilight until January 7th. The very young crescent Moon passes 3.2 degrees southeast of Saturn on January 13th. The Ringed Planet is in conjunction with the Sun on January 24th.
Uranus is located about half-way between fifth-magnitude star Xi Arietis and the sixth-magnitude 19 Arietis. The first planet to be discovered with a telescope reaches its second stationary point on January 14th. The waxing gibbous Moon passes 3.1 degrees southeast of Uranus on January 21st. Uranus is at eastern quadrature on January 26th. Visit http://www.nakedeyep....com/uranus.htm for a finder chart.
Neptune is located one degree east of the fourth-magnitude star Phi Aquarii. The waxing crescent Moon passes 4.1 degrees southeast of Neptune on January 17th. The eighth planet sets before 9:00 p.m. local time as January ends. Browse http://www.nakedeyep...com/neptune.htm for a finder chart.
Finder charts for Uranus and Neptune are also available online at https://skyandtelesc...W_WebFinder.pdf
See http://www.curtrenz.com/uranep.html for additional information on the two outer planets.
The dwarf planet Pluto is in conjunction with the Sun on January 14th.For more on the planets and how to locate them, browse http://www.nakedeyeplanets.com/
A summary on the planets for January can be found at https://skynews.ca/j...ts-at-a-glance/
The graphic at https://www.timeandd...lanets/distance displays the apparent and comparative sizes of the planets, along with their magnitudes and distances, for a given date and time.
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/
Asteroid 16 Psyche shines at tenth magnitude as it glides northwestward through Taurus about 1.5 degrees north of Aldebaran. Asteroids brighter than magnitude +11.0 that reach opposition this month include 15 Eunomia (magnitude +8.4), the largest stony asteroid, on January 21st, 14 Irene (magnitude +9.3) on January 24th, and 10 Hygiea (magnitude +9.9) on January 28th. See http://asteroidoccul.../2021_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 various asteroids.
During January, Comet 88P/Howell travels northeastward through Aquarius this month. The faint periodic comet passes relatively close to Neptune by the end of January. The fragmented Comet 141P/Machholz 2 heads towards Mira (Omicron Ceti) from the vicinity of Neptune this month. Comet 17P/Holmes, which brightened to second magnitude in 2007, lies to the west of Comet 88P/Howell. Visit http://cometchasing.skyhound.com/ and http://www.aerith.ne...t/future-n.html for information on these and other comets visible this month.
An article titled Sky Highlights for 2021 appears on pages 48-50 of the January 2021 issue of Sky & Telescope.
Another article on some of the astronomical events taking place in the coming year can be found at https://www.universe...he-coming-year/
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 [C]. 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 3rd, 6th, 9th, 12th, 15th, 18th, 21th, 23rd, 26th, and 29th. 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 15th, centered at 2:12 a.m. EST. Minima can also be observed on the night of January 17th, centered at 11:01 p.m. EST, and on the evening of January 20th, centered at 7:50 p.m. EST. Consult page 50 of the January 2021 issue of Sky & Telescope for the times of the minima. See http://stars.astro.i.../sow/Algol.html and http://www.solstatio...ars2/algol3.htm for more on Algol.
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/
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
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.