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RABaker

Sunnyvale, US
731 posts

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RABaker Registered since 01st Oct 2003
Thu 18-Oct-12 10:48 PM | edited Fri 19-Oct-12 04:30 PM by RABaker

Here is my first successful image of M31 (Andromeda galaxy) from last January. Of course it also includes the small elliptical galaxy M32 (left of Andromeda's center) and the slightly larger elliptical (spherical?) galaxy M110 (below and to the right of Andromeda's center). I had tried to image Andromeda previously from my very light-polluted backyard in Sunnyvale, CA with rather miserable results. This image was taken at a reservoir about a one hour drive away where the sky is noticeably darker.
Lens: Nikkor 300mm f/4 ED AFS
Aperture: Approx. f/6.8 (manually set between 5.6 and 8)
Camera: QHY-8 (6MP dedicated CCD astro-camera) (Note that the camera's sensor is the same physical size as the Nikon DX cameras)
Mount: Orion Sirius GoTo equatorial mount
Guide scope: Orion Short Tube 80
Guide camera: Orion StarShoot Autoguider

This image is a stack of 27 10-minute sub-exposures taken over two nights, captured with Nebulosity software and processed with Nebulosity and PixInsght. Earlier attempts with the Nikkor 300mm lens at wider apertures showed considerable coma on stars away from the center of the image. Even at f/6.8 there is still some visible coma, but nowhere near as bad as at wider apertures. Because the images from the two nights were not centered exactly the same, there was some cropping done to eliminate the areas where the stacked images did not coincide. I am still learning to process astroimages, and especially having trouble with color balance, but this was the best I could do. I plan to try this target again to see if I can improve on my results.


Click on image to view larger version


Attachment#1 (jpg file)

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