Experiments with LP Filters on M101

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Some of you know that I have been taking way too many subs of M101 recently.  If you don’t want to know what I learned about light pollution filters, then just skip to the fourth photo and enjoy M101.
 
The idea was to see how well the Baader Light Pollution Moonglow filter with IR cut works.  I was also wanting to compare taking shorter subs (60-90 seconds) at 240 gain with longer guided subs at 90 gain. 
 
Here are the results:
 
M101 35 frames at 60 seconds each, no filter, 240 gain, no visible moon
M101 35 frames at 60 seconds each, no filter, 240 gain, no visible moon, core difficult to process
M101, 37 frames at 90 seconds each, no filter, 240 gain no moon, core difficult to process
M101, 37 frames at 90 seconds each, no filter, 240 gain no moon, core difficult to process
M101, 10 frames at 360 seconds each with LP filter, 90 gain and 88% moon. Core easy to process. Very grainy. Color too red
M101, 10 frames at 360 seconds each with LP filter, 90 gain and 88% moon. Core easy to process. Very grainy. Color too red.
M101, 17 frames at 360 seconds each with LP filter, 90 gain, no moon, Core easy to process, Color easy to process.
M101, 17 frames at 360 seconds each with LP filter, 90 gain, no moon, Core easy to process, Color easy to process.

Looking very closely at the details, I think the second and fourth pictures are very similar. I think the fourth picture would have won hands down if I had taken the subs early through much less atmosphere.

I am amazed at how well the nearly full moon picture came out. Visually, I cannot even see M101 through my 10 inch Meade when the moon is out, much less find it in a 5 inch Mak.

I want to see if I can choose about 150 gain instead of using the defaults at 0, 90, and 240. That would let me take 240 to 300 second pictures instead of 360 second pictures which would increase the amount of light and might reduce the number of shots with satellites in them.

I figured out how to use groups in DeepSkyStacker to combine subs from different nights and have each night corrected with its own set of flats.

I think I’m done with this study because there are other targets I want to capture. Here’s looking forward to another night under the stars (hopefully Monday).