M103 - an Open Cluster in Cassiopeia
M103 - an Open Cluster in Cassiopeia
M103 - an Open Cluster in Cassiopeia
At a distance of approximately 8,000 light years, M103 is one of the farthest open clusters in our Milky Way Galaxy. The cluster contains about 40 stars with some catalogs identifying as many as 172 stars. The garnet star in the center of the cluster is a red giant.

In this image, North is up. This image is cropped to 56% of the original full frame.

Exposure Details
Lens Celestron C-8 SCT with Celestron focal reducer
Focal Length 1160mm
Focal Ratio f/5.8
Mount Schaefer GEM - 7 1/2 Byers gear
Guiding ONAG On-Axis Guider, Lodestar autoguider, PHD Guiding
Camera Canon 450D - Gary Honis modified
Exposure 88 subexposures of 180 seconds each at ISO 100 - about 4 1/2 hours total
Calibration 30 darks, 30 flats, 30 bias
Date September 30, 2012
Temperature 63F
SQM Reading 18.9 (Bortle 6 - Moon was Full)
Seeing 1/5
Location Pine Mountain Club, California
Software Used Images Plus 4.5 for camera control, calibration, stacking, digital development, multiresolution sharpening, smoothing and noise reduction. Registar used for stack alignment. Photoshop CS5 used for levels and curves, color correction, selective color, match color, star shrinking, lab color, and saturation adjustments. Gradient Xterminator for gradient removal. Carboni Tools for additional saturation adjustments, noise reduction, and smoothing. HLVG for additional color correction.
Notes The seeing was horrible the evening I captured this image, and the Moon was Full. As such, this isn't an impressive photo. Nonetheless, the cluster has some beautifully colored stars, and at least I was able to add one more object towards a complete Messier catalog!