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Skylights:Winter 2016

Well, here we are again - Winter, the best time for us northern hemisphere observers to look at the night sky. It's just a pity that it has to be in the cold! Never mind, wrap up well and enjoy the season of long dark nights and the brightest stars in the sky.

Low down in the south east, Sirius the brightest star in the sky, twinkles like a diamond. The twinkling is due to currents and dust in the atmosphere, its brightness is due to the fact that Sirius is fairly close to us at about 9 light years. It also has a tiny White Dwarf companion, composed of such dense material that it pulls Sirius about in a tiny eliptical orbit. It was this effect that indicated its presence long before we had a telescope big enough to show it.

Above Sirius and to the west we encounter the constellation of Orion. Orion is an easy constellation to find due to the three second magnitude stars in a line that represent the Mighty Hunter's belt. But it is just below the 'belt' that we find the 'Sword' and the magnificant Great Orion Nebula, number 42 in Messier's catalogue (M42).Visually, through the telescope, M42 resembles a patch of mist towards the centre of which are the four tiny brilliant stars of the Trapezium. These are the powerhouse, that causes the dust and gas of the nebula to glow with such brilliancy that we can just see it with the naked eye despite the fact that it is some 1600 light years away. Look carefully and you will see a dark intrusion like a ahadow close to the centre. This is a dark nebula comprized of cold dark material much of it organic and is the birth place of stars and planets. We can only see a tiny part of this Great Nebula, long exposure photographs show it to be a huge and complex object with many billows and streams covering a good part of the whole constellation.

But, Orion has other wonders to offer. The star that marks his shoulder Betelgeuse, is a massive Red Giant. If Betelgeuse was our 'Sun', we would be inside it and so would be Mars. Betelgeuse is a vast bloated star soon to undergo a phase change when it will colapse as the outward radiation pressure will become less than the gravitational force. It has already thrown off a shell of gas about 100,000 years ago.

The brightest star in Orion represents his foot, Rigel is a brilliant blue-white first magnitude star. A remote Supergiant, Rigel lies somewhere between a 1000 to 1400 light years away and has a luminosity over 60,000 times that of the Sun. Rigel is also a double star with a faint 7th magnitude companion at about 12 o'clock visible in a 6-inch telescope.

There are other interesting objects in Orion but we should move onwards and upwards to encounter Taurus the Bull whose eye is represented by the first magnitude orange star Aldebaran, another Red Giant situated at about 19 parsecs. To the west of Aldebaran is the open star cluster the Hayades. The Hyades is an old cluster in contrast to the Pleiades above and to the west, which is composed of hot, young, blue stars. Easily seen with the naked eye, the cluster has 7 main stars, called the 'Severn Sisters' but through a telescope there are over 90 stars to be seen. Long exposure photography shows the whole cluster drifting through pale blue nebulosity.

Almost on the zenith (point overhead), is the first magnitude star Capella,principal star of Auriga - the charrioteer. Auriga contains three bright star clusters, M36, M37 and M38. All of which require a small telescope and a dark nightv to do them justice

Close to the zenith is the familiar 'W' shape of Cassiopeia, below which we might just about locate the central bulge of the Andromeda Galaxy M31, it is the most distant object that we can see with the naked eye at 2.25 million light years! As I often say "you can see a lot further in the dark".

Below and to the east of Cassiopeia lies Perseus. Its principle star Mirfak lies in a rich star field and is a fine sight in binoculars. Sweeping up towards Cassiopeia we will encounter the Double cluster in Perseus.Two compact clusters set against the Milky Way a wonderful sight on a clear dark night.

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

If you fancy a more detailed view of the objects and events described on this page our observatory will be open to the public at the appropriate times and weathers (consult the local listings).

Overview

Of the planets, Mercury Returns to the evening sky but rises barely 5 degrees above the horizon and sets barely half an hour after sunset. Venus is also an evening object but also a bit low at about 10 degrees above the horizon but rising to 10 drgrees by the end of the year. Marsis just about as low as it can get and sets about an hour after sunset. Jupiter is now moving into the dawn sky by the end of the year but you will need to get up early! Saturn is now lost to view behind the Sun. Uranus is an evening object in Pisces and Neptune is an evening object in Aquarius.

Meteor showers to note:. The Geminids December 13th Max. but described as unfavourable this year. and Quadrantids January 4th described as quite favourable.

[The night sky from
Hampstead: winter 2017]

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Moon

The Moon is one of the most impressive sights through a telescope. Even in a pair of binoculars it can amaze. 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.

  [Full Moon] [Last quarter] [New Moon] [First quarter]
Phase Full Moon Last quarter New Moon First quarter
Date 14/12 21/12 29/12 07/12
Date 12/01 19/01 28/01/10 05/01
Date 11/02 18/02 26/02 04/02

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Comets

Comets are also sometimes visible and can produce incredible public interest, like Comets 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. Most recently, Comet Lovejoy graced our skies but is now too distant and feint. Normally none can be seen with the unaided eye at any given time but this can change. To stay abreast of this sign up for our news service.

To prove this point Comet Holmes suddenly brightened in October 2007 by about one million times to be visible to the naked eye in Perseus. Admittedly this is unusual, as comets give more notice with this level of change. Comet Holmes has now faded and lost to sight.

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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). 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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Last modified: Dec. 4th 2016 DGD