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February 2010 Celestial Calendar

Dave Mitsky

Note: All times in UTC (EST + 5)

The famous astronomers Nicolas Copernicus, Galileo Galilei, and Clyde Tombaugh were born this month.

During the first two weeks of February, the zodiacal light can be seen in the western sky after sunset from dark locations.

A lunar occultation of the Pleiades can be seen from Africa and southern Europe on the evening of February 21. See http://www.lunar-occultations.com/iota/pleiades/pleiades.htm for additional information. The Moon is 16.7 days old and is located in Sextans at 0:00 UT on February 1. It's at its greatest northern declination of +25.7 degrees on February 23 and its greatest southern declination of -25.7 degrees on February 8. Latitudinal libration is at a maximum of +6.8 degrees on February 4 and a minimum of -6.7 degrees on February 18. Longitudinal libration is at a maximum of +7.8 degrees on February 5 and a minimum of -7.4 degrees on February 21. 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 the constellation of Capricornus on February 1.

Brightness, apparent size, illumination, distance from the Earth, and location data for the planets and Pluto on February 1: Mercury (magnitude -0.2, 6.2", 71% illuminated, 1.08 a.u., Sagittarius), Venus (magnitude -3.9, 9.8", 100% illuminated, 1.71 a.u., Capricornus), Mars (magnitude -1.3, 14.1", 100% illuminated, 0.67 a.u., Cancer), Jupiter (magnitude -2.0, 33.4", 100% illuminated, 5.90 a.u., Aquarius), Saturn (magnitude 0.7, 18.8", 100% illuminated, 8.85 a.u., Virgo), Uranus (magnitude 5.9, 3.4", 100% illuminated, 20.82 a.u., Pisces), Neptune (magnitude 8.0, 2.2", 100% illuminated, 30.98 a.u., Capricornus), and Pluto (magnitude 14.1, 0.1", 100% illuminated, 32.55 a.u., Sagittarius).

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

Visibility of the classical planets at midmonth from 40 degrees north latitude: Mercury can be seen during morning twilight; Venus is very close to the horizon at morning twilight; Mars transits the meridian at 11:00 p.m. EST and sets at 6:00 a.m. EST; Jupiter is very close to the horizon at morning twilight; Saturn rises at 8:00 p.m. EST and transits at 3:00 a.m. EST.

Mercury can be found seven degrees above the horizon on the morning of February 1. The speedy planet is seven degrees from a thin crescent Moon on February 11 and four degrees from an even thinner crescent Moon the next morning. Mercury brightens from magnitude -0.2 to magnitude -0.6 during February.

Venus begins an evening apparition this month. Venus and Jupiter are two degrees apart in the west-southwest on the evening of February 14, with a very thin 21-hour old crescent Moon to their west. The two planets are separated by just 33 arc minutes on February 16, when Venus is only 3 degrees above the horizon at sunset. On February 17, the distance between the two planets has increased to one degree. These events will be difficult to observe due to the proximity of the Sun.

Mars is slightly dimmer than Sirius (magnitude -1.4), the most brilliant star in the night sky, at the start of February but fades to only half the brightness of the Dog Star by the end of the month. The Red Planet decreases in apparent size by two arc seconds and retrogrades through Cancer during February. Its northern hemisphere, which is undergoing spring, is tilted towards the Earth. Syrtis Major lies near the central meridian at 11:00 p.m. EST on February 17. The bland side of Mars is visible at the start and the end of the month. A map of Martian surface features appears in the December 2009 issue of Sky & Telescope. Sky & Telescope's Mars Profiler, a valuable online resource for identifying surface features can be found at http://www.skyandtelescope.com/observing/objects/javascript/3307831.html

Jupiter is about a half a degree north of Venus on February 16 and is in conjunction with the Sun 12 days later.

Saturn moves from one degree north of the fourth-magnitude star Eta Virginis at the start of February to two degrees northwest of the star by the end of the month. The tilt angle of Saturn's rings decreases from five to four degrees during February. Eight-magnitude Titan is north of Saturn on February 2, southwest of Saturn on February 10, northeast of Saturn on February 18, and southwest of the planet on February 26. Eleventh-magnitude Iapetus lies three arc minutes west-southwest of Saturn on the night of February 1. Iapetus brightens to tenth magnitude and is about ten arc minutes from Saturn when it's at greatest western elongation on February 17. For further information on Saturn's satellites, browse http://www.skyandtelescope.com/observing/objects/javascript/3308506.html

Uranus is visible early in the month approximately 5 degrees south of the fifth-magnitude star Lambda Piscium in the Circlet of Pisces. It vanishes into the glare of the Sun by the end of February.

Since Neptune is in conjunction with the Sun on February 14, it can't be seen this month.

Pluto is not readily observable during February.

Two ninth magnitude comets grace the skies this month - C/2007 Q3 (Siding Spring) and the periodic comet 81P/Wild. Comet 81P/Wild passes approximately five degrees north of the first-magnitude star Spica (Alpha Virginis) during the night of February 6. On the night of February 17, the tail of Comet C/2007 Q3 (Siding Spring) is nearly edge-on with respect to the Earth. Visit http://cometchasing.skyhound.com/ for additional information on these comets.

Asteroid 4 Vesta and the seventh-magnitude star HD 89930 are less than one arc minute apart at 6:00 a.m. EST on February 13. Vesta passes between the second-magnitude binary star Algieba (Gamma Leonis) and the fifth-magnitude star 40 Leonis during the night of February 16. On February 18, Vesta shines at magnitude 6.1 as it reaches opposition. The minor planet is 18 arc minutes west of Algieba that night.

A free star map for February 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 February 2, 5, 8, 10, 13, 16, 19, 22, 25, and 28. 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 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)

Challenge binary star for February: 15 Lyncis (Lynx)

Notable carbon star for February: BL Orionis (Orion)

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.