This image is the result of my Fast Imaging project in an attempt to produce my most detailed image of Messier 81 (also known as NGC 3031 or Bode's Galaxy) which is a grand design spiral galaxy about 12 million light-years away in the constellation Ursa Major.  This project began in December of 2023 and though a lot of trial and error, research, and a high electric bill, I finally found the best way to capture and process this subject.  Over 100,000 images were taken but only a total of 52,464 sub exposures were kept as I tried from 0.1 second all the way to 30 second exposure times but settled on 21,834 x 1 second and 29,210 x 2 second sub exposures in broadband then 1,420 x 30 second sub exposures using a IDAS NBZ-II to capture the faint Ha.

Why fast imaging?  Glad you asked 🙂. I was never able to image galaxies because they would get lost in the light pollution.  This technique seems like it helps a lot!  Here is an excellent lecture given by Robin Glover that where I got the idea: https://www.youtube.com/watch?v=3RH93UvP358

I created a python script to measure the Median Absolute Deviation (MAD) of each image in it's calibrated, mosaic state and created a graph to show the outliers to remove.  After debayering, the broadband images were aligned and stacked using PixInsight's new FastIntegration process and with the drizzle files that it produced, I then bayer drizzled at 1x by 0.9 drop shrink to remove interpolation artifacts.  The narrowband images were aligned and stacked using WBPP and also drizzled the same way 1x by 0.9.  Once the broadband image was processed, I then using continuum subtraction, added the faint Ha to the broadband image.

This project took so long as I battled the weather, equipment failures, and balancing with a busy work schedule and family life.  In the end, I learned a new way to capture images from my even more light polluted location, bad seeing, clouds, and sometimes poor guiding to produce a detailed closeup view of M81 only using only an 8 inch Ritchey Criterion telescope!  I have wrote a post on Astrobin's forum here showing how I used PixInsight's FastIntegration process as I want to help other achieve what I have done!

Special thanks to James aka nateman_doo on the Cloudy nights forum for his creation of a adapter to decouple the imaging train from the primary mirror of my TS-Optics RC8 Telescope: https://www.cloudynights.com/topic/827768-finally-made-an-rc-collimation-adapter/ and Nick @Supro for selling me his RC8 which was in excellent condition.

Clear Skies!
Dave