NGC2403 Image

Posted on March 12, 2015 by Denis

I have finished an image of NGC2403, a fine galaxy in Camelopardalis, and have posted it in my gallery.  This galaxy is a member of the M81 group and is approximately 8 million light-years distant.  There is a bright emission nebula and open cluster within the galaxy that has its own NGC number, NGC2404.  I reproduce my image here with the location of NGC2404 indicated.

NGC2404 Revealed

This image is my most ambitious effort yet with my Obsession dobsonian.  It is composed of 1221 subs, each of 10s duration, for a total of 203.5 minutes of total exposure.  The images were captured on February 14, 15 and 16, 2015 at Zephyr Ridge Observatory.  I used Pixinsight software for processing.

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NGC7331 Image

Posted on January 20, 2015 by Denis

I have posted my latest effort in my image gallery, an image of NGC7331, a famous galaxy in Pegasus.  I reproduce the image below.

NGC7331

The data for this image were acquired on August 24 and 27, 2014.  I encountered some difficulties during processing as some of my subs exhibited an unusual red glow that caused bands in the final integrated image.  I am not sure what happened to these subs, but after much trial and error, I found a way to use most of them in my final image thanks to the power of Pixinsight image processing software.  But, I still had to discard 176 of the 800 subs I acquired (each of 10 seconds duration).  Most of these were not suitable due to blurry/elongated stars that result from unguided exposures on a dobsonian mount.  And with the considerable field rotation I experienced during the duration of these exposures, I had to crop most of the field away.  The end result is not up to the standard set by those with equatorial mounts with autoguiding.  But, my humble collection of images demonstrates that it is possible to achieve reasonable results with a dobsonian telescope.

Denis

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