The evening sky of December ’15 has no planetary attraction. Saturn that was above the western horizon for last few months is now too close to the sun to be seen. It will reappear at dawn above the eastern horizon by the end of the month.
Mercury can be seen above the western horizon after 3rd week of December. It reaches greatest eastern elongation on 29th of December. It would set almost an hour and a half after the sunset. It is rather an easy object to catch from latitudes closer to the equator. It is about -0.5 magnitude object. It is said that Copernicus who suggested that the planets go round the sun had never seen this planet.
The morning sky has Jupiter, Mars and Venus with Arcturus (Swati) and Spica (Chitra) above the eastern horizon. Earth is catching up with the other two outer planets. Jupiter brightens up from -2.0 to -2.2 mag and its angular size increases from 35.6 to 38.9 arc sec. Angular size of Mars increases from 4.8 to 5.6 arc second but it’s magnitude actually decreases from 1.3 to 1.5 as its phases decreases from 0.93 to 0.91.
As distance between Earth and Venus continues increase it’s phase too increases from 0.69 to 0.77 and angular size decreases form 16.2 to 14.3 arc seconds and but the magnitude remains close to -4.1.
Watch march of Moon past these planets from 4th to 8th December. On 4th Dec it will be 3 deg south west (a bit above and to the right) of Jupiter. On 5th it is half way between Jupiter and Mars. Then on 6th it is right above Mars. On 7th Moon is close to Spica with Venus 6 deg below it. Finally on 8th thin lunar crescent can be seen right below Venus.
So far we talked about the planets those can be seen ‘easily’ with naked eyes. Uranus which was discovered using a telescope is just within the naked eye limit. It is nearly overhead this month and can be spotted easily using a small telescope. It is about 5.8 mag object with 3.5 arc second angular size.
The table below give list of astronomical phenomena. This list is generated Occult V4.0.9 by David Herald of International Occultation Timing Association.
d h (in UT) 2 10 Regulus 2.8N of Moon 3 7 LAST QUARTER 4 5 Jupiter 1.7N of Moon 5 15 Moon at apogee 6 2 Mars 0.1N of Moon Occn 6 23 Spica 4.3S of Moon 7 17 Venus 0.7S of Moon Occn 10 14 Saturn 3.1S of Moon 11 10 NEW MOON 12 7 Moon furthest South (-18.4) 13 9 Pluto 3.1S of Moon 17 6 Neptune 2.5S of Moon 18 15 FIRST QUARTER 19 19 Mercury 3.8S of Pluto 20 1 Uranus 1.1N of Moon Occn 21 8 Moon at perigee 22 04:47 Solstice 23 19 Aldebaran 0.7S of Moon Occn 23 23 Mars 3.5N of Spica 25 7 Moon furthest North (18.4) 25 11 FULL MOON 26 11 Uranus stationary 29 0 Mercury greatest elong E(20) 29 19 Regulus 2.6N of Moon 31 16 Jupiter 1.4N of Moon Phases of the Moon (timings in IST hh:mm) Last quarter: 03-Dec 13:10 New moon: 11-Dec 15:59 First quarter: 18-Dec 20:44 Full moon: 25-Dec 16:41 Minima of Algol in IST (times from John D. Sabia's java script 3 Dec 23:45 8 Dec 20:34 21 Dec 04:40 24 Dec 01:29