Messier 37 (M37)

Also Known as: NGC 2099, Collinder 75

Object Type: Open Cluster

Constellation: Auriga

Distance from Earth: 4,511 light years

Apparent Magnitude: 6.2

Coordinates: RA 05H 52M 18S DEC 32 deg 33 min 02 sec

Actual Size: 20 to 25 light years in diameter

Apparent Dimensions: 24 arc-minutes

Discovered by: Messier 37 was discovered by the Italian astronomer Giovanni Battista Hodierna before 1654.
Guillaume Le Gentil missed the cluster when he discovered the nearby Messier 36 and Messier 38 independently in 1749, even though M37 is brighter and larger than the other two.
Charles Messier re-discovered M37 in 1764.

Description: M37 is the brightest, richest, and largest of the 3 open clusters in Auriga.
The other two open clusters are M36 and M38.
Messier 37 lies in the direction opposite to the galactic center when seen from Earth. It is between 347 and 550 million years old and contains at least 12 evolved red giant stars.
The hottest main sequence star in the cluster has the stellar classification B9 V. Messier 37 is classified as Trumpler type I, 1, r or 1,2 r, which means that it is a detached cluster with strong central concentration (I), that its stars either have almost the same apparent brightness (1) or a moderate range in brightness (2), and that ithe cluster is richly populated (r), with more than 100 members.
Messier 37 contains more than 500 confirmed members, of which over 150 stars are brighter than magnitude 12.5. The cluster has a mass of 1,500 solar masses.
It orbits through the Milky Way with a period of 219.3 million years, coming within 19,600 light years of the galactic center at its nearest approach and moving to a distance of 30,700 light years at the farthest point in its orbit.

Click Below Image(s) for Full Size:

Small telescopes reveal a dozen of the brightest stars and an 8 inch scope reveal several hundred stars.
In 10x50 binoculars M37 appears as a hazy patch of light, but 20x80 and larger binoculars reveal a very compact star cluster resolving the brightest stars.

The best time of year to observe M37 is in the winter months December-February.

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M37 Open Cluster

Imaging Details
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