OJBs Web Site: M41

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M41

Here's the basic information for M41. Its a type "e" open cluster type "e" in Canis Major, also known as NGC 2287 or the Little Beehive. Location is at right ascension 06h 46.0m, declination -20° 44m. The distance is about 2300 light years. The visual brightness is magnitude 4.6, and the apparent size is 38 arc minutes (true size is about 26 light years). It contains about 100 stars, the brightest is a magnitude 6.9 orange star of true brightness 700 times the Sun. There is also a bright blue star (12 CMa, magnitude 6, true brightness 380 Suns) in the field but this is not part of the cluster and is only about half its distance. M41 is thought to be around 200 million years old. It has been known since the 17th century and might have been known to Aristotle.

Its easy to find M41 because it is only 4° from the brightest star in the sky, Sirius (magnitude -1.47, true brightness 27 times the Sun). This puts M41 and Sirius in the same field of most binoculars. Canis Major has a distinctive dog shape as shown above upside down (Sirius is the shoulder, Beta is the front leg). You can use Sirius and Beta Canis Majoris to form a triangle and locate M41.

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