M48 - NGC 2548

Messier 48 (NGC 2548) is a large open cluster in the constellation Hydra, located approximately 1,500 light-years from Earth. It contains roughly 80 stars within a diameter of about 23 light-years and shines at a combined apparent magnitude of about 5.8, making it marginally visible to the naked eye under excellent conditions. The cluster is estimated to be around 300 million years old. Like M47, M48 was for a long time considered a "lost" Messier object because Messier recorded its position with an error of about 5 degrees in declination. The true identity of M48 was established by T.F. Morris in 1959 and independently confirmed by Owen Gingerich, who demonstrated that NGC 2548 matches Messier's description and is the only viable candidate in the general area. The cluster was originally observed by Messier on February 19, 1771. M48 spans about 54 arcminutes, larger than the apparent diameter of the full Moon, making it a fine target for binoculars and wide-field telescopes at low magnification. Through binoculars, it appears as a bright, irregular concentration of about 50 stars with a distinctive triangular or wedge-shaped arrangement in its brighter members. A small telescope reveals the full extent of the cluster, including a mix of blue-white main-sequence stars and a handful of yellow and orange giants that provide subtle color contrast. The cluster lies in a relatively star-poor region of Hydra, which actually works in its favor by making it stand out more prominently against the background. M48 is an underappreciated object that deserves more attention from observers, as it is quite attractive when viewed with the appropriate low magnification.

Contains about 80 stars spanning 23 light-years at a distance of 1,500 light-years, covering 54 arcminutes of sky with an age of 300 million years.