Adrian Dening's Stars Over Somerset

Wednesday, 16 February 2022 17:00

Monday 21st to Sunday 27th February 2022

An open cluster of stars is defined as a group of up to several thousand stars that were formed in the same molecular cloud and are held together by each other's gravity. All the stars within a cluster will be a similar age and they gradually drift apart over many millions of years.

If you look fairly high up towards the south east around midnight next week, it is possible to see the open cluster of stars known as Melotte 111 with the naked eye. Firstly find the constellation of Coma Berenices which is located between the constellations of Bootes and Leo. The cluster will be situated slightly to the right of Coma Berenices.

Although the cluster had been known about for a long time, Charles Messier never bothered to include it in his catalogue of deep sky objects, so it doesn't have an "M" number. Back in 1915, a British astronomer called Philibert Melotte included it in his list of star clusters and it was number 111 that he recorded, hence the name. The cluster contains around 40 brighter stars that are approximately 280 light years away from us and the brightest of these form an obvious "V" shape.

On Thursday 24th around 9pm, the constellation of Gemini reaches its highest position in the night sky towards the south. There will be no light pollution from the Moon because it will be below the horizon, so it's an ideal time to spot an open cluster that Charles Messier did bother to catalogue! The cluster is known as M35 and it is much fainter, so you will need to use binoculars or a small telescope. This cluster is a lot further away from us - around 3,800 light years. It is located near the foot of one of the Gemini twins.

Screenshots courtesy of Stellarium
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