December 2010

The Moon

New ------------- 5th up from 07:59 to 15:19
First Quarter - 13th up from 11:48 to 00:30
Full ------------- 21st up from 15:59 to 08:26
Last Quarter -- 28th up from 00:20 to 11:17

On the 21st, there will be a Total Lunar Eclipse, visible from Doncaster, if you get up at 6:35am to see it start. It’ll be full at 7:45am, but will have set by 8:30am, on a clear horizon. It’ll be in the northwest as the Moon goes down. The Sun will be rising in the southeast and casting the Earth’s shadow onto it.


Planets in December.
Saturn will rise in the east on the 1st of December at 3am; followed by bright Venus at 4:30am, in Virgo at the start, but moving into Libra on the 12th. They’ll set on the 1st at 2pm for Saturn and 20mins later for Venus. They’ll start the month 16° apart, but spread to 36° by the end of the month, Venus having to return for a closer circuit of the Sun.
On the 31st, Saturn will rise at 1am so will have gained 2 hours, while Venus will rise at 4:30am. Saturn will then set at midday and Venus at 1:30pm.
Mars will be unavailable all month, being too close to the Sun. Mercury will become available from the 23rd, with care, as always with Mercury. It’ll rise about an hour before the Sun, so will be low and in bright twilight, not a good prospect, but it’ll get better, till by the 31st, it’ll be rising 100 mins before the Sun, and though half the size of Saturn will be twice as bright, lower down though. Bright Venus will be between them in the last week of the year. On the last day, a crescent Moon will rise close to Venus, to add to the picture. The scene on morning of the 2nd will be even better as Saturn will also be there, with bright Spica between them.
Neptune will rise on the 1st of December at 12:30pm, broad daylight, followed by the pairing of Jupiter, at mag –2.6 and 43arcsec, and Uranus at 1:30pm. They’ll set on the 1st, at 10pm for tiny Neptune, mag 8 and 2arcsec, and at 12:30am for Jupiter and Uranus. At the end of the month Neptune will rise at 10:30am. Jupiter and Uranus, at mag 5.8 and 4arcsec, will join it at 11:30am. Neptune will set at 9:30pm and Jupiter and Uranus at 11pm.

Comets.
There aren’t any comets currently worth seeking, the only ones available will need big telescopes or long exposure photographs to be seen. Though if you use the internet to go to http://www.minorplanetcenter.org/iau/ephemerides/comets, you will find there a long list of comets. Click on your choice and its ephemerides will be screened. Ephemerides? Predicted position of heavenly bodies, they tell you where they’ll be on certain dates. You’ll also find tons more data than you can shout at, but look for the line “Download this Ephemeris as a KML file”. Click on it to download it. It should settle on your PC’s desktop or wherever you choose. When it’s arrived, click on the file, or double click if necessary, and it’ll wake up google Earth, if you have that on your machine, and present you with a message suggesting you switch to google Sky. Click on Switch to Sky, and it’ll show you the track of the comet, with dates and all sorts of other data. Nicely done, Mr. Google.

Meteors Showers.
The Geminids, peaking on the 14th of December with 120/hour at the zenith, is the one to go out for. Get very warmly dressed, find a dark place, soon after dark, lay down on a garden lounger with a blanket over you and watch. Look mostly directly upwards, but face towards the east, as the radiant, in Gemini, will be rising there. No, don’t look directly at the radiant, as you’ll see only those coming directly at you. These meteors are debris from the asteroid Phaethon, and are slow and frequently big and bright. The best shower of the year, if permitted by cloud and Moon, which will be at first quarter but nearer the west, so less of a problem.
The Ursids will also be there, peaking on the 22nd, but 10/hour at most is less of a draw. It’s radiant is near Kochab, the lead star in Ursa Minor, quite close to the Pole. The Moon will be a good way to the west and should be less of a problem, but it will be near Full.

If you should need any detailed sky charts, please get in touch at www.donastro.org.uk .
This also applies to passages of the ISS and Iridium Flares, but you’ll find it easier to get them from www.heavens-above.com.