27-10-2007 November night sky (Article 109)

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Simon Kenny
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Location: Shannon, Co. Clare, Ireland

27-10-2007 November night sky (Article 109)

Post by Simon Kenny » Wed Feb 04, 2009 11:31 am

November night sky (Article 109)

Sometimes the interesting things in the night sky are at inconvenient times.
For November we suggest one very attractive object called The Pleiades
(pronounced ‘Plydayz’) requiring nothing but your own ‘peepers’ to observe and is on view at a most reasonable time.
Known as an ‘open star cluster’ its catalogue no. is M45. The letter ‘M’ refers to the Messier no. The Frenchman Charles Messier created a catalogue of 103 most prominent star clusters, nebulae and galaxies and each one was given an ‘M’ no. A few more were added to this list by other astronomers. A far more comprehensive listing, containing many thousands of objects, is the New General Catalogue (NGC). Both the Messier and NGC nos. remain in use by astronomers.

As always with astronomical objects, an appreciation of what you are looking at enhances the enjoyment. The Pleiades (M45) is the brightest and most famous star cluster in the sky and popularly called The Seven Sisters after a group of mythological nymphs, the daughters of Atlas and Pleoine. When your eyes are dark adapted after 20 minutes away from lights, about 7 stars are visible to the naked eye. Binoculars are best to see the whole cluster and bring many more stars into view (the image below is what you might see with 7 X 50 binoculars). This star cluster covers about 3 full moon widths in the sky, so a telescope will only see part of the cluster. Formed approx. 50 million years ago, it contains some 100 stars (many of them are blue giants) and lies about 400 light years away. The whole cluster lies in a faint nebulosity which is the remains of the gas cloud from which the stars formed. A long exposure photograph would capture this nebula but even binoculars or small telescopes, under good conditions, can glimpse some of the nebula.

Interested? On 1st Nov. at 9pm look east, about 30º up from the horizon in the constellation Taurus and you cannot mistake it. It will gradually climb higher through the month and by 30th at 9pm it will be 40º up, looking ESE. Clear skies

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