Lum:; 11 X 2 min binned 1 X 1
RGB: 8 X 2 min binned 2 X 2
Globular cluster Messier 30 (M30, NGC 7099), at about 26,000 light years distance and about 90 light years across, and appears to us under an angular diameter of about 12.0 arc minutes. It is fairly dense (as its concentration class V indicates), and a fine object in even small telescopes. Its brightest red giant stars are about of apparent visual magnitude 12.1, its horizontal branch giants at magnitude 15.1. Only about 12 variable stars have been found in this globular cluster. A color-magnitude diagram (CMD) of M30 can be found in Richer et.al. (1988). Its overall spectral type has been determined as F3, and its color index was given as B-V=0.60 mag. It is approaching us at 181.9 km/s.
