SUPERCEDED-NEWER VERSION AVAILABLE---NGC 253 - The Silver Dollar Galaxy in Sculptor
SUPERCEDED-NEWER VERSION AVAILABLE---NGC 253 - The Silver Dollar Galaxy in Sculptor
SUPERCEDED-NEWER VERSION AVAILABLE---NGC 253 - The Silver Dollar Galaxy in Sculptor
NGC 253 is the largest galaxy in the Sculptor group of galaxies. Visually, the galaxy is quite large - about 28' x 6'. This is the width of the full moon (although much fainter and thinner!). At magnitude 8, it is a fairly easy object to see in a telescope, although it is always quite low for us in the Northern Hemisphere.

In this image, North is Up. This image is cropped to 94% of the original full frame.

Exposure Details
Lens Celestron C-8 SCT with Celestron focal reducer
Focal Length 1260mm
Focal Ratio f/6.3
 
Mount Schaefer GEM - 7 1/2
Guiding 80mm f/11 guidescope with PHD Guiding
 
Camera Canon 20Da
Exposure 54 subexposures of 150 seconds each plus 28 exposures of 300 seconds each at ISO 1600 - about 4 1/2 hours total exposure
Calibration 30 darks, 30 flats, 30 bias
 
Date September 26 and 27, 2011
Temperature 59F on 9/26, 51F on 9/27
SQM Reading
Seeing 3 of 5 on both nights
Location Pine Mountain Club, California
 
Software Used Images Plus 4.0 for camera control, calibration, stacking and digital development. Photoshop CS5 used for flat fielding , curves, color Correction and saturation adjustments, star shrinking, and high pass filter. HLVG for additional color correction, Carboni Actions for additional saturation adjustments.
Notes This was a difficult object to photograph because it never rises above 30 degrees at my latitude. I think the final result came out rather well. I have some Hydrogen Alpha data to add to this when time permits.

This image was chosen Digital Astro Challenge Photo 1st place for September 2011 in the Galaxy Category.

I subsequently reprocessed this image to be much improved. The reprocessed version is HERE.

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NGC 253 - The Silver Dollar Galaxy in Sculptor