Skylights: Winter 2011

On December 20th the Sun attains its most southerly declination, nights are long, the sky is dark (except for light pollution) and the splendours of the winter constellations are once more on display. Due south, straddling the meridian is Orion - the Mighty Hunter, easily recognised by the three second magnitude stars that comprise his 'belt'. Below his belt is located M42 the Great Orion Nebula a veritable star factory. In moderate telescopes it appears as a faint fuzzy patch with the four stars of the Trapezium at its heart. Long exposure imaging reveals the complexity of this beautiful nebula. Great billows and swathes of nebulosity cover a large area of the constellation. It is a wonderful sight in the telescope on a clear dark night. Orion's principal star Betelgeuse which translates as 'the Shoulder of the Giant' is an old red giant. Contrast the colour with that of Rigel beta Orionis marking Orion's foot. Rigel is a young hot blue star and it has a very faint companion at 12 o'clock seen with some difficulty in a 6-inch telescope.

Above Orion and to the west is the constellation Taurus the Bull. The Bull's eye is marked by another red giant Aldebaran and following it is the naked eye double Theta Tauri, part of the old open star cluster the Hyades. Higher up and further to the west is another star cluster the Pleiades sometimes called the 'Seven Sisters'. The Pleiades are comprised of young energetic blue stars and long exposure imaging shows the swathes of blue nebulosity that envelops them. At least seven stars are visible to the unaided eye and binoculars or a small telescope will resolve many more. To the west of Taurus lies the small constellation of Aries the Ram which this year plays host to the planet Jupiter, looking like a very bright star.

Almost on the Zenith the point directly overhead, is the bright first magnitude star Capella the principal star in Auriga - the Charioteer. The Milky Way sweeps through Auriga (if only we could see it!) and there are several nice star clusters to be found M36, M37, and M38. All are fine sights with a small telescope and good targets for photographers.

East of Auriga we find the two first magnitude stars Castor and Pollux marking the heads of Gemini the 'Twins'. Castor is a close binary star and in the western part of the constellation is yet another nice star cluster M35. Looking further east we encounter the faint asterism of Cancer the 'Crab' which contains another star cluster M44 Praesepe the 'Beehive' cluster. A very low power and wide field of view are required to see this at its best.

Further east still we find Leo the 'Lion' against which is moving the planet Mars which is in opposition in March. Contrast the distinctly red hue of Mars with the blue tint of Regulus the main star in Leo situated at the bottom of a 'sickle' of fainter stars.

Returning to the meridian, low in the south east Sirius the 'Dog Star' sparkles away. Sirius is the brightest star in the sky and fairly close at just 9 light years. These are just a few of the gems to be found in the winter sky - wrap up warm, brave the cold and have a look at them.

The sky map below shows the general appearance of the night sky and there are sections giving more detail about planets, the Moon, comets and others.

Overview

Of the planets, Mercury attains greatest eastern elongation on the 14th of November but will not be visible from the UK. Venus returns to the evening sky at the beginning of December but will be low down very close to the horizon. Mars is an early morning object in Leo it is still a long way off and presents only a tiny disk. Jupiter Is well placed for observation in Aries and visible for most of the night. Saturn Is just returning to the pre-dawn sky in Virgo, just north of Spica. Uranus is visible in the evening sky situated in Pisces. Neptune is amongst the faint stars low down in Aquarius

Meteors to note are the Geminids Max on December 14th. Described as the richest of the annual showers with slow moving meteors and a good proportion of bright events. And possibly the Ursids maximum on December 23rd. Not a well known shower that has provided outbursts in the past and is described as very favourable this year.

[The night sky from
Hampstead: Autumn 2011 v]

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Moon

The Moon is one of the most impressive sights through a telescope. Even in a pair of binoculars much detail can be seen. The best times to view the Moon is about 3 days before and after first quarter, when the Moon is in the evening sky. Also there's the added bonus that the terminator (line between light and dark) is visible and we get some spectacular views of the lunar surface seen in high relief.


Phase	Full Moon	Last quarter	New Moon	First quarter
Date	10/12/11	18/12/11	24/12/11	02/12/11
Date	09/01/12	16/01/12	23/01/12	01/01/12
Date	07/02/12	14/02/12	21/02/12	31/02/12
Date	08/03/12	15/03/12	22/03/12	01/03/12

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Comets

Comets are also sometimes visible and can produce incredible public interest, like Comet Halley (1985-86) and Hale-Bopp (1997). In 2005 Comet Machholz was visible and Comet McNaught scudded through the northern sky in January 2007 and was easily accessable to the naked eye, albeit for just a few days. Normally none can be seen with the unaided eye at any given time but this can change. This was certainly the case with Comet Holmes which increased its brighness by a million times in October 2007 and remained visible to the naked eye for many weeks. During March 2009 Comet Lulin was moving westwards below Leo but it was a very faint object and not at all easy to locate.

There are currently no significant comets moving across the sky that are within our range apart from Comet Garradd which can be found just to the east of the 'keystone' in Hercules close to Mu Herculis on January 3rd. At a predicted magnitude of 7.5 it should be visible in binoculars. To stay abreast of any new comets, sign up for our news service.

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Other animals

Most of the phenomena above are reasonably periodic. But there are also sporadic events which we can see through the Cooke telescope like eclipses or even novae and supernovae (Please). And last summer (2010) we had another unexpected comet/asteroid collision with Jupiter seen from Australia. So keep your eyes on the skies or let us do it for you and you might get to look at some rare, beautiful and profound phenomena.

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