Messier Number: M3
NGC Number: NGC 5272
Object Type: Globular cluster
Distance in Light Years: 31,000
Constellation: Canes Venatici
Apparent Magnitude: 6.2
M3 contains an estimated half a million stars and is visible to the naked eye under very good conditions. It is just below the limit of visibility under average conditions.
With binoculars, it appears as a hazy, nebulous patch. A 4-inch telescope shows a bright compact core within a round, mottled, grainy glow, which uniformly fades towards the outer edges. A 4-inch does not resolve the cluster but, under good conditions, shows some of the brightest stars. A 6-inch telescope resolves the outer two-thirds into faint stars with a background glow of unresolved fainter stars. An 8-inch shows stars throughout the cluster except in the core, which is resolved by telescopes of 12 inches upwards.
