Messier 50 or M50 (also designated NGC 2323) is an open cluster in the constellation Monoceros. It has an apparent visual magnitude of 6.3 and its angular diameter is 16 arc-minutes. M50 lies at an estimated distance of 3000 light years. The Equinox 2000 coordinates are RA= 7h 03.2m, Dec= -08° 20´ which makes M50 best seen during the winter. The Messier Winter Star Chart shows the position of all Messier objects visible during that season.

The image above shows the uncropped view of M50 through the Takahashi E-180 Astrograph (North is up). A 3x enlargement of this image appears to the right. About 7 arc-minutes south of the cluster's center is a red M class giant, which contrasts strongly with the neighboring blue-white stars.

While it is included in the Messier Catalog, this open cluster was first discovered by G. D. Cassini in 1711. According to Kharchenko et al. (2005), the distance of M50 is 2870 light years and its diameter is 13 light years. It contains 2050 stars and its estimated age is 100 million years.

For more information, see the Messier Catalog as well as specific entries for M50 in Wikipedia and SEDS.

Messier's Description of M50

April 5, 1772
`Cluster of small stars, more or less brilliant, above the right loins of the Unicorn, above the star Theta of the ear of Canis Major, and near a star of 7th magnitude. It was while observing the Comet of 1772 that M. Messier observed this cluster. He has reported it on the chart of that comet, on which its trace has been drawn. Mem. Acad. 1772.'

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