M48

M48 is a large, bright open cluster in Hydra, about 2,500 light-years from Earth. It contains roughly 80 stars spread across about 23 light-years, with an age of about 300 million years. The cluster features a prominent triangular pattern of bright stars along with several orange and yellow giants among its blue-white members.

Located in a relatively sparse region of Hydra, about 3 degrees southeast of Zeta Monocerotis. Visible to the naked eye from dark sites. Binoculars show a large, scattered group with a triangular core pattern. A telescope at 40-60x provides the best view, showing about 50 stars with nice color variety. The cluster spans about 30 arcminutes, so moderate magnification is ideal. Best observed from January through April.

Discovered by Charles Messier on February 19, 1771, but with an error in recorded position. Like M47, this led to M48 being 'lost' until the mid-20th century. It was identified with NGC 2548 by T.F. Morris in 1959.