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Astronomy Picture of the Day

Cancer

Cancer

Cancer, which is a small and not very prominent constellation, lies between Gemini and Leo. It contains one A-List object - M44, the Beehive Cluster sometimes called Praesape, the latin for manger.

M44 Open Star Cluster E B L

M44 M44 (08:40:24.000 +19:41:00.00 FK5 J2000) Open (galactic) Cluster

M44 can be seen with the unaided eye as a misty patch just over 1 degree in diameter, extended slightly in a north-south direction. It lies in the triangle formed by Delta, Gamma and Eta Cancri. Overall it is of 3rd magnitude. However, the 15 brightest stars have magnitudes between 6.3 - 7.5, so those with keen eyesight should be able to resolve individual stars under perfect conditions! Binoculars or a small telescope resolve the misty patch into about 40 stars, whilst larger telescopes will show up to 200. They range down to magnitude 14 of which 80 are brighter than magnitude 10. It is at a distance of 577 light years and was formed about 730 million years ago. It is a little surprising that the Beehive Cluster was included in Messier's catalogue as this was designed to be a catalogue of objects that might be confused with a comet. It was added just before the first Messier catalogue was published in 1771. Another star cluster, the Pleiades - M45, also not typical of the Messier objects, was added too. It is suspected that these might have included in his catalogue along with the two nebulae in Orion so that it would contain more objects than that published by Lacaille in 1755!

Position: 08h 40.1m +19deg 59min