Mercury: at magnitude -0.8, starts the month in the constellation Libra. Mercury is a morning object, but too close to the Sun. Best seen from 5.7h - 6.5h. (On November 1st, RA=13h28m25s Dec= -7°43.0' (J2000) Distance=0.791AU Elongation= 15° Phase k=22% Diameter=8.5")
Venus: is a morning star of magnitude -4.2, The planet is in constellation Virgo at the start of the month. On the 11th Venus crosses into Libra. It is best seen from 3.8h -14.3h. Venus was at Perihelion (distance to sun: 0.718 AU) on the 30th November. (On December 1st, RA=13h39m24s Dec= -7°58.9' (J2000) Distance=0.947AU Elongation= 44° Phase k=66% Diameter=17.6")
The Moon is at Perigee on the 22nd Deceber 10:21 UT, (distance to earth center: 360828.7km) and at apogee on the 6th, at 17:04.3 UT (distance to earth center: 406212.2 km). The Moon is close to the Pleiades on the 21st.
Mars: at magnitude -1.3 starts the month in the constellation Gemini. The planet is best seen from 17.5h - 7.3h. Mars is in retrograde this month and moves in the opposite direction to normal against the stars. It crosses back into Taurus, the Bull on the 30th; it will not reappear in Gemini until March 2008. Mars is at opposition this month. Mars makes its closest approach To Earth on December 19th. The planet is one degree north of the bright star Epsilon Geminorum on the 2nd. The Moon Occults Mars on the 24th. (On December 1st, RA= 6h45m57s Dec=+25°27.4' (J2000) Distance=0.618AU Elongation=149° Phase k=97% Diameter=15.2")
Jupiter: is still bright at magnitude -1.8 in the constellation Ophiuchus. The planet is conjunction with the sun and is difficult to observe this month. The planet is best seen from 15.8h -16.7h. (On December 2nd, RA=17h43m33s Dec=-23°10.1' (J2000) Distance=6.197AU Elongation= 16°) The planet Jupiter is a source of huge radio storms. Click the link to hear the live audio stream. The radio outbursts are in the frequency range 18 - 32 MHz. Sensitive receivers translate Jupiter's radio waves to audio sounds. For alternative listening site. for Great RedSpot Transit times. Check forum for Satellite predictions.
Saturn: at magnitude 0.7 sits in the constellation Leo. The planet emerges is a morning object this month, rising in the eastern skies just after midnight. The planet is near the moon on December 1st. A waning gibbous Moon is near Saturn again, on the 29th. The planet is best seen from 23.2h - 7.3h. (On December 1st, RA=10h41m38s Dec= +9°57.1' (J2000) Distance=9.187AU Elongation= 91°) for interactive Saturn moon calculator .
Uranus is in the constellation Aquarius, near Lambda Aquarii, magnitude 3.7. Uranus at magnitude 5.8, has a bluish-green hue and appears 3.7 arcseconds wide. The planet is visible now in southern skies during early evening.; this very dim object can be seen in binoculars or better still, small telescope, as a very blue-green starlike object. The planet is best seen from 17.3h -23.3h. The moon is lose to the planet on the 16th. (On December 2nd,RA=23h04m48s Dec= -6°44.6' (J2000) Distance=19.991AU Elongation= 95°)
Neptune: in the constellation Capricornus less than 3 degrees northeast of the 4.3 mag star Iota Capricornii. The planet is low in the southwestern sky during early evening. A telescope will usually show a tiny bluish dot, only 2.5 arcseconds wide (mag 7.9). Neptune is best seen from 18.6h -19.6h. The moon is lose to the planet on the 14th. (On November 1st, RA=21h26m36s Dec=-15°21.4' (J2000) Distance=29.851AU Elongation=100°)
Pluto is in the constellation Sagittarius (mag 13.9) is not visible in the southern sky this month. Normally, a finder chart is necessary to help in identifying the 0.1" diameter dwarf planet. The dwarf planet is best seen from 18.0h - 5.9h. (On December 1st, RA=17h51m24s Dec=-17°05.0' (J2000) Distance=32.307AU Elongation= 20°)
The Sun enters the zodiac sign Capricorn on the 22nd December.
Highlights: Winter Solstice on December 22nd. This is officially the longest night of 2007, er, even though the year's earliest sunset occurs two weeks earlier. The Geminid meteors on the night of the 13th-14th. Watch out for this reliable shower. Capricornus, the Sea Goat: Sign of the Zodiac for birth dates between 22 December and 19 January; it is the leading constellation of the "wet" or "water" constellations. Capricornus has a symmetrical shape resembling a bikini bottom, but the stars of Capricornus are very faint with no star brighter than the third magnitude. Capricornus appears low in the southern sky (never at higher altitudes). The Tropic of Capricorn (23.5 degrees South latitude) is named after Capricornus; on 22 December (on average), the Sun is directly overhead (at the zenith) at Noon along the Tropic of Capricorn. In Mythology, the Greeks identified Capricornus with Pan, the god of nature, who was pictured as half-man, half-goat. In fear, Pan escaped the giant Typhon by leaping into the Nile River and changing his tail to that of a fish. This is the origin of the word, "panic."
2007 12 06 Moon at apogee, 406,235 km 17 UT 2007 12 14 Meteor shower peak -- Geminids 2007 12 22 Winter (Northern Hemisphere) begins at the solstice, 6:08 UT 2007 12 22 Moon at perigee, 360,813 km, 10 UT 2007 12 24 Mars at opposition, 20 UT
There are many meteor showers this month... The Geminid Meteors Shower Peaks on the night of the 13th-14th. A thin crescent moon does not hamper this reliable shower. The Coma Berenicids are a poorly-known minor shower, and badly need more observing. Very swift meteors, (65km/sec). Their Radiant is at RA 11h40m Dec +25°. Ursids Meteor ShowerPeaks on the 17th. A minor shower. The peak is predicted about 2200 UT. The radiant (RA 14h28m Dec +76°) is circumpolar (It never sets in northern locations). The meteors are generally slow (33km/sec) and rates are lower than the Geminids, but certainly above the background sporadic count. The Ursids are linked with Comet 8P/Tuttle (period around 13.5 years; last at perihelion in 1994). Their peak rates can be quite variable Also, watch out for sporadic meteors. Their rates for the Northern Hemisphere are now reaching a plateau. Expect around 12 random meteors per hour during the morning hours
Earth and Mars are converging December is Mars month. Look in the constellation Gemini on the first of the month at 8 p.m. About 20 degrees above the horizon, you will see Mars right on Castor's leg. Mars will make its closest 2007 approach to Earth this month, on Dec. 19, and should be a great telescopic object about 55 million miles distant. Mars will not be this close again until 2016. On Dec. 23, the nearly full moon passes with only 1/2 degree of the Red Planet, both within the field of a telescope at low power. By the end of December, Mars retrogrades into Taurus, the Bull. Retrograde simply means that the planet appears to move ''backwards'' against the starry background.