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January 2010 Celestial Calendar

Dave Mitsky

Note: All times in UTC (EST + 5)

The astronomer Johannes Hevelius (1611-1687) was born this month.

The Quadrantid meteor shower peaks on the morning of January 3 but is compromised by strong moonlight. This shower can sometimes reach zenithal hourly rates of more than 100 meteors per hour. The radiant of the Quadrantids lies at the junction of the constellations of Boötes, Hercules, and Draco in what was once called Quadrans Muralis. The near-Earth asteroid 2003 EH1 is believed to be the source of these meteors.

The Moon is 15.5 days old and is located in Gemini on January 1 at 0:00 UT. See http://www.lunar-occultations.com/iota/bstar/0111zc2366.htm for information on the lunar occultation of the first-magnitude star Antares on January 11. The largest Full Moon of 2010 takes place on January 30. Tides will be larger than normal on January 31. The Moon is at its greatest declination north of +25.8 degrees on January 26 and its greatest declination south of -25.8 degrees on January 12. Latitudinal libration is at a maximum of +6.9 degrees on January 7 and a minimum of -6.9 degrees on January 22. Longitudinal libration is at a maximum of +7.2 degrees on January 8 and a minimum of -7.8 degrees on January 24. Visit http://www.astronomyblogs.com/member/saberscorpx/?xjMsgID=50821 for tips on spotting extreme crescent Moons. Times and dates for the lunar light rays predicted to occur this month are available at http://www.lunar-occultations.com/rlo/rays/rays.htm

The Sun is located in Sagittarius on January 1. On January 15, the longest annular solar eclipse until 3043 occurs in Africa and southern and eastern Asia.

Data (magnitude, apparent size, illumination, and distance from the Earth in astronomical units) for the planets and Pluto on January 1: Mercury (2.9, 9.6", 6%, Sagittarius, 0.70 a.u.), Venus (-4.0, 9.8", 100%, Sagittarius, 1.71 a.u.), Mars (-0.8, 12.7", 96%, Leo, 0.74 a.u.), Jupiter (-2.1, 35.0", 99%, Capricornus, 5.64 a.u.), Saturn (0.9, 17.8", 100%, Virgo, 9.32 a.u.), Uranus (5.9, 3.4", 100%, Aquarius, 20.60 a.u.), Neptune (8.0, 2.2", 100%, Capricornus, 30.88 a.u.), and Pluto (14.1, 0.1", 100% , Sagittarius, 32.68 a.u.).

Visibility of the classical planets at midmonth from 40 degrees north latitude: Mercury can be seen during morning twilight; Mars is visible the entire night; Jupiter sets at 8:00 p.m. EST; Saturn rises at 11:00 p.m. EST and culminates at 5:00 a.m.

Jupiter and Uranus lie in the southwest evening sky. At midnight, Mars is in the southeast and Saturn is in the east. Mercury can be seen in the southeast, Mars in the west, and Saturn in the southwest in the morning.

Mercury is in inferior conjunction on January 4. For observers at 40 degrees north, Mercury is 9 to 10 degrees above the horizon a half hour before sunrise from January 15 to the end of the month. Greatest western elongation takes place on January 27.

Venus reaches superior conjunction on January 11 and is not visible this month.

Earth is at perihelion on January 3. On that date, it is about 3% (5.0 million kilometers or 3.1 million miles) closer to the Sun than on July 6, when Earth is at aphelion.

In early January, Mars rises about 7:00 p.m. and culminates around 2:00 a.m. EST. It begins to retrograde westward from Leo into Cancer during the second week of January, moving from west of the Sickle of Leo to the vicinity of Gamma Cancri, a total of ten degrees. Mars increases in apparent size by 1.4 arc seconds and brightens by more than half this month. Mars is nearest to the Earth on January 27, when it's at a distance of 93.3 million kilometers (61.7 million miles). When the Red Planet reaches opposition - a rather unfavorable one - on January 29, it shines at magnitude -1.3 and subtends 14.1 arc seconds. However, although it is quite small in angular size, Mars does have a favorable northern declination of 22 degrees and 10 minutes at opposition, when it will be less than four degrees to the northeast of the bright open cluster M44. The northern hemisphere of Mars, which is experiencing springtime, is tipped towards Earth. This means that the northern polar cap will be particularly prominent. The following Martian surface features are near the central meridian at midnight EST on the indicated dates: Sabaeus Sinus, Mare Acidalium, and Chryse Planitia (January 1); Sabaeus Sinus, Syrtis Major, and Hellas (January 7); Syrtis Major and Hellas (January 14); Mare Cimmerium, Mare Sirenum, Elysium, and Amazonis (January 21); Solis Lacus and Tharsis (January 28). When viewed at the same time from one night to the next, Martian surface features seemingly rotate 9 degrees backward each night. A map of the surface features of Mars appears in the December 2009 issue of Sky & Telescope. Sky & Telescope's Mars Profiler, a valuable online resource for identifying Martian surface features can be found at http://www.skyandtelescope.com/observing/objects/javascript/3307831.html

Jupiter moves from Capricornus to Aquarius this month. It sets about four hours after sunset at the start of January and less than two hours after the Sun by the end of the month. Jupiter's four major moons were discovered by Galileo Galilei four hundred years ago this month. Data on the Galilean satellites is available at http://skytonight.com/observing/objects/javascript/3307071.html#

On the first night of 2010, Saturn rises at approximately 11:30 p.m. EST. It's situated less than half a degree north of the celestial equator, about one degree north of the fourth-magnitude star Eta Virginis. The inclination of Saturn's rings is 4.9 degrees, the greatest amount of ring tilt from October 2008 through August 2010, on the morning of January 8. Saturn begins retrograde (western) motion on January 14. Titan is near Saturn on January 2, 10, 18, and 26. Iapetus is at greatest eastern elongation on January 10. For additional information on the satellites of Saturn, browse http://www.skyandtelescope.com/observing/objects/javascript/3308506.html

Uranus bids farewell to Aquarius and enters Pisces, residing just south of the Circlet of Pisces. The seventh planet is greater than 40 degrees in altitude on the first day of January at the end of twilight and sets late in the evening, about two hours after Jupiter. As it heads towards conjunction in March, Uranus appears lower in the sky with each successive night.

Neptune is located approximately two degrees to the west of Jupiter in early January. By the end of the month, Neptune disappears into evening twilight as it approaches conjunction on February 14.

Finder charts for Uranus and Neptune appear on page 59 of the September 2009 issue of Sky & Telescope and are posted online at http://www.skyandtelescope.com/observing/highlights/41561382.html

Pluto is not a viable telescopic target this month.

Asteroid 4 Vesta shines at seventh-magnitude as it glides northwestward through northern Leo during January. On the nights of January 1 and January 2, it lies between 46 and 52 Leonis. 4 Vesta is located just three arc minutes from a 6.6-magnitude star on the night of January 21.

Comet 81P/Wild passes southeastward through Virgo this month. The tenth-magnitude periodic comet lies one degree to the south of Saturn during the first week of January. Comet 88P/Howell and Siding Spring (2007 Q3) are two other possible cometary targets. Visit http://cometchasing.skyhound.com/ for additional information on these comets.

A free star map for January can be downloaded at http://www.skymaps.com/downloads.html

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on January 1, 4, 7, 10, 13, 16, 19, 21, 24, 27, and 30. For more on Algol, see http://stars.astro.illinois.edu/sow/Algol.html and http://www.solstation.com/stars2/algol3.htm

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)

Challenge binary star for January: 14 Orionis

Notable variable star for January: U Orionis

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

Top ten binocular deep-sky objects for January: 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.