Southern Sky News for 2009 December

Planet overview for December

With summer upon us, the Sun spends more time in the sky than a few months ago, cutting down our star gazing time. From Cape Town, it begins to get dark around 20:38 in the evening, and by 04:07 the sky begins to brighten. The corresponding times for Johannesburg are 19:50 and 03:45.

This gives 7½ hours of darkness in Cape Town, and almost 8 hours in Johannesburg. Compare this with winter values of 11½ hours for Cape Town and 11¼ hours for Johannesburg.

The start of summer is marked on December 21 when the Sun reaches the December solstice; after this date the Sun slowly begins to move northward.

December boasts two Full Moons: the first on December 2, and the second on December 31 (a so-called "Blue Moon").

On this very last day of the International Year of Astronomy, the Blue Moon will also be eclipsed! This lunar eclipse will be very subtle, with only the tip of the Moon turning a gentle reddish colour as the Moon just skims through the Earth's shadow. The best time to watch will be for 20 minutes or so starting at 21:00 on December 31.

In the evening sky after sunset this month, Jupiter shines prominently in the west and is visible for the first half of the night. Jupiter is the brightest 'star' in the evening sky at the moment so it does duty at Evening Star this month.

Mercury is low in the west at sunset this month, and is best seen around midmonth. It lies amongst the stars of Sagittarius, setting low in the west at nightfall. On the 9th and 10th, look for Mercury shining as a jewel set on the lid of the Teapot asterism.

Before sunrise, Mars and Saturn can be seen in the sky. Mars already rises late at night and sits high in the sky in the morning, while Saturn rises several hours after the Red Planet and is an early-morning object low in the east.

Venus won't be visible this month as it lies too near the Sun to be seen.

Prominent constellations in December

As soon as night falls, the beautiful starry region of Orion and Taurus, and the brilliant stars Sirius and Canopus, decorate the eastern horizon. Binoculars will reveal many beautiful star clusters in this area, of which the Pleiades (Seven Sisters) is the most brilliant.

Few things are more sublime than scanning the starry heavens on a lovely summer's evening.

Star gazers diary for December

Date	dow	Things to look out for
01	Tue	Look out for the Moon on the horizon around sunset. After nightfall, notice the Pleiades just above the Moon, and the Hyades and Aldebaran (in Taurus) to the right.
02	Wed	Look out for the Full Moon on the horizon around sunset.
05	Sat	In the morning sky, the Moon lies above Castor and Pollux in Gemini.
06	Sun	Mars is to the bottom-right of the Moon, visible after midnight.
07	Mon	Mars is near the Moon, with Regulus (in Leo) to the right.
08	Tue	Regulus (in Leo) near the Moon; Mars further left.
09	Wed	After midnight, look for the Last Quarter Moon between Saturn (right) and Regulus (left).
10	Thu	The Moon lies above Saturn.
11	Fri	Spica (in Virgo) is near the crescent Moon; Saturn to the left.
16	Wed	New Moon.
18	Fri	Mercury is best seen tonight shortly after sunset. The crescent Moon lies very low in the west-southwest at sunset and will be a challenge to see. "Stars to Midnight" with Jurg and Rita Wagener at Sutherland.
19	Sat	Crescent Moon lies low in the west-southwest at sunset; Mercury shines to the bottom-left, and Jupiter top-right. "Stars to Midnight" with Jurg and Rita Wagener at Sutherland.
20	Sun	The crescent Moon is visible in the west at sunset; Jupiter above, Mercury low down to the bottom-left.
21	Mon	The crescent Moon is visible in the west at sunset, with Jupiter to the left.
21	Mon	Summer solstice.
22	Tue	At sunset, look for the crescent Moon in the west with Jupiter to its left.
24	Thu	First Quarter Moon.
25	Fri	Christmas Eve; the bright Moon lies above Pegasus, midway between Jupiter and Aldebaran (the Bull's Eye).
31	Thu	Second Full Moon this month (“Blue Moon”). Tonight's partial lunar eclipse will not be very prominent; it begins at around 20:55 and ends at 23:25, with maximum eclipse at 21:22.

Happy star gazing!

/ph

Reader's comments

Posted by Doug Rhodes on Tuesday, 2009 December 22 @08:30.

I am a beginner in the "star watch" game and find this sight invaluable in preparing for the nightly "events" well in advance, get the 'scope ready etc.
Also to date most of the available information is Northern, so again, residing in Melbourne I find your web site terrific.

Posted by Charlotte on Wednesday, 2009 December 23 @03:49.

How generous of you to make all these beautiful high-quality downloads available at no cost! Thank you so much.

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