The Binocular Sky


M3 (NGC 5272)

Constellation: CVn
Object Type: Globular Cluster
RA:  13h 42m 11s
Dec:  +28° 22' 33"
Magnitude: 6.2
Recommended minimum aperture: 50mm

Charts for 100mm Binocular (2.5° aperture circle).   Click on a chart to print it.


I usually find M3 by imagining the intersection of a line from Cor Caroli (α CVn) to Arcturus (α Boo) with one from β Com to ρ Boo; if M3 is not in the field, it is slightly towards Arcturus. Alternatively, start your hop at β Com. M3 is 2½ fields E. It is a degree S of a line joining β Com to ρ Boo.

What You Should See:

M3 is a large, bright, obvious cluster which, at ×37 shows distinct brightening to the core. It is only slightly smaller than the better known M13 (18 arcmin vs. 10 arcmin) and, in my opinion, is a better binocular object. This is because it is "looser" around the periphery and hence requires less magnification to resolve the outer stars.

The 6th magnitude star slightly to the SW is yellowish.