Dreyer's description of NGC 2301 in his New General Catalog (NGC):
"Cluster, rich in stars, large, irregular figure, stars large & small."
Quote from: The Deep Sky Field Guide to Uranometria 2000, 2nd Ed:
"Open Cluster made up of 80 stars, the brightest being magnitude 8. Rich in stars; large brightness range; strong central condensation; detached from background star field."
Open Star Cluster NGC 2301 in the Constellation of Monoceros is easy to see in backyard telescopes. It is located in a wonderful area of the winter Milky Way a little east of the Constellation of Orion. Many sky guides start a description of this cluster as "often overlooked" because of the many fine objects in the area. The bright yellow/red star on the left of the image has a much different motion across the sky than NGC 2301, and thus is probably not a part of the cluster.
There is much recent professional research on this cluster. The latest age estimate is 210 million years and a recent distance estimate is 1,650 light years. While the catalogs list this cluster as covering 12 arc minutes, recent studies show outliers at 10 arc minutes from the center, meaning that the cluster fills the image above. Many of the cluster's stars are variables, with five being eclipsing variables, and another 133 appear to be stars whose variation is due to rotation modulated by star spot activity.
George Normandin, KAS
March 18th, 2010