M3 - Globular Star Cluster in
Canes Venatici
Copyright 2011 Hap Griffin
Date/Location:
February 18, 2011 Imaging Infinity
Observatory Bethune, SC
Discovered by Charles Messier in 1764, M3 is one of the brightest globular
clusters visible to us. While the brightest star in it is around Magnitude
11, the entire cluster shines at magnitude 6.4 and is easily grasped in
binoculars. Consisting of roughly a half million stars in a sphere 220
light-years in diameter, it is approximately 10 billion years old and orbits our
Milky Way galaxy, currently heading towards us with a radial velocity of 90
miles per second.
M3 lies at a distance of 40,000 light years.
Camera: QSI 583wsg
Filters: Astrodon E Series Generation 2 LRGB
CCD Temperature: -20 C
Instrument: Planewave 12.5" CDK
Focal Ratio: f/8
Mount: AP-1200
Guiding: Auto via the QSI camera's built in Off-Axis Guider
mirror and an SBIG ST-402 Guider
Conditions: Cool and clear with nearly full moon
Weather: 60 F, still
Exposure: 54 minutes total (6 x 3 min each in RGB)
Capture: CCDAutopilot 4 w/ Maxim DL Camera Control, focused automatically w/
FocusMax
Processing: Frame calibrations, alignment and stacking with ImagesPlus v3.80.
Finishing in Photoshop CS5.