SUPERCEDED-NEWER VERSION AVAILABLE---NGC 253 - The Silver Dollar Galaxy in Sculptor
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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 |
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Mount |
Schaefer GEM - 7 1/2 |
Guiding |
80mm f/11 guidescope with PHD Guiding |
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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 |
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Date |
September 26 and 27, 2011 |
Temperature |
59F on 9/26, 51F on 9/27 |
SQM Reading |
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Seeing |
3 of 5 on both nights |
Location |
Pine Mountain Club, California |
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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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