M51 LRGB from Bortle 9
This was an interesting exercise and a bit of a brute force approach.
While waiting for a new deep sky telescope, I used the planetary Celestron C14 (non-edge version) with the very small pixeled 183 mono camera with 2.4 micron pixels.
The 4000mm focal length of the C14 was too long and lower by almost 0.5x with the Optec Nextgen reducer.
That reducer is only suitable for small sensors and has limited back focus so no OAG was possible. I had a 76mm triplet on top of the C14 as a guidescope (dew shield was used as well).
The backyard at the time was right by a highway with lights at a Bortle 9 location:
Below is a single 45s lum. sub after full calibration - which looked horrible:
The extreme light pollution and lack of an OAG forced me to use 45 second subs and some 900 subs were collected of which 628 x45s subs were selected and stacked with NSG in Pixinsight.
This is NSG integrated master light frame:
Pixinsight DBE was then used to get rid of most of the background glow. It took a lot of post processing work to pull details out of the image but it was there.
RGB data as later collected at a Bortle 6 location with a CDK12 and an Astrophysics 2.7" 0.75x reducer. Again, this reducer was not designed for that telescope.
A total of 35x 240s of subs of RGB were captured =
less 1 hour per channel.Overall, this is an example of
how NOT to image DSO objects:Extreme light pollution
Planetary telescope not designed for DSO imaging
Not properly guided
Very small pixels and extreme oversampling
Not much RGB data for color information
However, this is a good example of how powerful Pixinsight processing can be and one is able to render a decent image despite very poor circumstances.
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