January 2011 Celestial Calendar & Observing Notes c/o Dave Mitsky

[Big Dipper]

January 2011 Celestial Calendar & Observing Notes courtesy of Dave Mitsky (calendar data also reproduced in our forum calendar).

All times, unless otherwise noted, are UT.

1/2 Uranus is 0.6 degree north of Jupiter at 13:00; Mercury is 4 degrees north of the Moon at 15:00

1/3 The Earth is at perihelion (147,105,721 kilometers or 91,407,282 miles distant from the Sun) at 19:00; a double Galilean satellite shadow transit (Io’s shadow follows Ganymede’s) begins at 19:11

1/4 The Quadrantid meteor shower (40 to 120 or more per hour) peaks at 1:00; a partial solar eclipse takes place in western Asia, the Middle East, northern Africa, and most of Europe beginning at 6:40; New Moon (lunation 1089) occurs at 9:03

1/5 The latest sunrise of 2011 at latitude 40 degrees north occurs today;

1/8 The latest onset of morning twilight of 2011 at latitude 40 degrees north occurs today; Neptune is 5 degrees south of the Moon at 0:00; Venus is at greatest western elongation (47 degrees) at 16:00

1/9 Mercury is at greatest western elongation (23 degrees) at 15:00

1/10 A double Galilean satellite transit (Europa follows Callisto) begins at 3:50; the Moon is at apogee, subtending 29 arc minutes from a distance of 404,977 kilometers (251,641 miles), at 5:37; Uranus is 7 degrees south of the Moon at 15:00; Jupiter is 7 degrees south of the Moon at 17:00; a double Galilean satellite shadow transit (Io’s shadow follows Ganymede’s) begins at 21:07

1/12 The Lunar X (the 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 00:02 ; first Quarter Moon occurs at 11:31

1/14 Mercury is 1.9 degrees north of the bright emission nebula M8 (the Lagoon Nebula) in Sagittarius at 8:00

1/15 The Moon is 1.3 degrees south of the bright open cluster M45 (the Pleiades) in Taurus at 13:00; Venus is 8 degrees north of the first-magnitude star Antares (Alpha Scorpii) at 21:00

1/17 A double Galilean satellite transit (Io follows Ganymede) occurs at 21:52; the Moon is 0.9 degree south of the bright open cluster M35 in Gemini at 23:00

1/18 Venus is at its greatest heliocentric latitude north today; a double Galilean satellite shadow transit (Ganymede’s shadow follows Io’s) begins at 0:43

1/19 Full Moon (known as the Ice Moon, the Moon After Yule, the Old Moon, and the Wolf Moon) occurs at 21:21

1/21 Mercury is in the descending node today

1/22 The Moon is at perigee, subtending 33 arc minutes from a distance of 362,792 kilometers (225,428 miles), at 0:09; asteroid 23 Thalia (magnitude 9.1) is at opposition at 10:00; asteroid 3 Juno (magnitude 9.0) is stationary at 23:00

1/24 Asteroid 7 Iris (magnitude 7.9) is at opposition at 8:00

1/25 A double Galilean satellite transit (Ganymede follows Io) begins at 0:05; Saturn is 8 degrees north of the Moon at 10:00

1/26 Last Quarter Moon occurs at 12:57

1/27 Saturn is stationary at 8:00

1/28 The Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to occur at 2:33

1/30 Venus is 3 degrees north of the Moon at 4:00

1/31 Mercury is at aphelion today; asteroid 1 Ceres is in conjunction with the Sun at 1:00

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

The Quadrantid meteor shower peaks on the morning of January 4. 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, which may be an extinct comet, is believed to be the source of these meteors. An article on the Quadrantid meteor shower appears on pages 40 and 41 of the January issue of Sky & Telescope. Browse IMO Meteor Shower Calendar 2011 | International Meteor Organization and Quadrantids for more on the Quadrantids.

The Moon is 26.3 days old and is located in Libra on January 1 at 0:00 UT. The Moon is at its greatest declination north of +24.2 degrees on January 16 and its greatest declination south of -24.2 degrees on January 2 and January 29. Latitudinal libration is at a maximum of +6.7 degrees on January 24 and a minimum of -6.8 degrees on January 10. Longitudinal libration is at a maximum of +5.1 degrees on January 2 and +6.0 degrees on January 28 and a minimum of -6.7 degrees on January 16. Visit Extreme Lunar Crescent Data [L1089-1102] | Saber Does The Stars for tips on spotting extreme crescent Moons. Times and dates for the lunar light rays predicted to occur this month are available at Lunar Sunrise/Sunset Crater Rays

The Sun is located in Sagittarius on January 1. A partial solar eclipse that is visible from the western portion of the eastern hemisphere takes place on January 4. Greatest eclipse occurs at 8:50:35 UT. For more on this event, see Partial Eclipse of the Sun: 2011 January 04 and NASA - Eclipses During 2011

Data (magnitude, apparent size, illumination, and distance from the Earth in astronomical units) for the planets and Pluto on January 1: Mercury (0.1, 8.0", 38%, 0.84 a.u., Ophiuchus), Venus (-4.6, 27.1", 46%, 0.62 a.u., Libra), Mars (1.2, 3.9", 100%, 2.38 a.u., Sagittarius), Jupiter (-2.3, 38.7", 99%, 5.09 a.u., Pisces), Saturn (0.8, 17.2", 100%, 9.65 a.u., Virgo), Uranus (5.9, 3.4", 100%, 20.29 a.u., Pisces), Neptune (8.0, 2.2", 100%, 30.68 a.u., Capricornus), and Pluto (14.1, 0.1", 100% , 32.93 a.u., Sagittarius).

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

Mercury is four degrees north of the Moon on January 2. Greatest western elongation takes place on January 9, at which time the speedy planet shines at magnitude -0.3.

On the first day of 2011, Venus rises nearly four hours before the Sun. The fifth-magnitude star Theta Librae lies just 2 arc minutes south of the planet on January 7. Venus reaches greatest western elongation on January 8.

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 at aphelion on July 4.

Mars is not visible this month.

Jupiter is now about 25% smaller in apparent size than it was at opposition last September. It sets at approximately 11:00 p.m. EST at the start of January and prior to 9:30 p.m. EST by the end of the month. Data on the Galilean satellites is available at SkyandTelescope.com - Interactive Observing Tools - Jupiter's Moons Javascript Utility

Saturn is located about 4 degrees south of the celestial equator. It is situated about two degrees from the fourth-magnitude star Theta Virginis for the entire month. Saturn rises approximately 12:30 a.m. EST on January 1. The ring tilt angle is ten degrees on that date. Eighth-magnitude Titan is due north of Saturn on January 4 and January 20 and due south of the planet on January 12 and January 28. Iapetus shines at tenth magnitude when it reaches greatest western elongation on January 4. Its brightness decreases by a magnitude on January 24, when it’s two arc-minutes north of Saturn. For additional information on the satellites of Saturn, browse SkyandTelescope.com - Interactive Observing Tools - Saturn's Moons Javascript Utility

Uranus is 0.6 degree north of Jupiter on January 2. By month’s end, the two planets are almost four degrees apart. The next geocentric conjunction of the two planets will take place in 2024.

Neptune is located approximately 2.5 degrees to the west of the fourth-magnitude star Iota Aquarii. The planet sets before 8:00 p.m. EST at mid-month. By the end of January, it can no longer be seen.

Pluto is not visible this month.

Asteroid 37 Fides (magnitude 10.4) passes through the northern portion of M45 (the Pleiades) during January.

Comet 103P/Hartley heads northeastward through Canis Major this month. The fading periodic comet passes very close to the open cluster M50 on January 31. Visit Comet Chasing for information on this month’s comets.

A free star map for January can be downloaded at Skymaps.com - Publication Quality Sky Maps & Star Charts

The famous eclipsing variable star Algol (Beta Persei) is at a minimum, decreasing in magnitude from 2.1 to 3.4, on January 3, 6, 9, 12, 15, 18, 21, 23, 26, and 29. For more on Algol, see Algol and Algol / Beta Persei 3

The famous pulsating variable star Mira (Omicron Ceti), the Wonderful, may still be visible to the naked-eye this month. Click on Mira, Omicron Ceti for further information on Mira.

The Mira-type variable star R Geminorum (7h7m21s, +22d42'12") should be near a maximum brightness of magnitude 7.1 in early January. R Geminorum is an unusual S-type variable. It has a period of 370 days and varies in brightness by some eight magnitudes. An article on R Geminorum appears on page 39 of the January issue of Sky & Telescope.