Discovered by Giovanni Batista Hodierna before 1654.
M37 is a dense open cluster located approximately 4,500 light years from the Earth in the constellation Auriga. The cluster has am estimated population of about 500 stars of which 150 are brighter than magnitude 12.5. M37 has a relatively large number of red giant stars along with hot main sequence blue stars. The age of the cluster is estimated to be between 347 and 550 million years. The cluster spans an angular dimension of 24 minutes of arc which equates to about 20 to 25 light years in diameter.