M4 - Globular Cluster in Scorpius
From the author of Sizing Up The Universe
Click here for Hertzsprung-Russell diagram.
22:18pm EDT Jun 15, 2006.
Starlight Express SXV-H9 on Tak FSQ106 at f/5.
L = 20 min, R = 3 min, G = 6 min, B = 9 min
(guided 1-minute subexposures).
Limiting sky mag:
L = 14.3.
Log stretch, Unsharp mask.