Imaged M81 (Bode's Galaxy( in OSC RGB on the nights of April 24/28/29, 2022.

This was my first galaxy image using a new imaging setup with my trusty C8 for higher magnification deep sky imaging of galaxies this spring.  Imaging a 1200 mm focal length is proving much more challenging then my usual 400 mm focal length wider field setup.  The toughest part has been the guiding.  I am tossing about 1/2 to 2/3 of my subs due to large guiding errors.  In part this setup is pushing my AVX mount, but at times I am getting down to 1 arcsec rms guiding, so it has promise.  I've decided to switch from guiding off a guide scope to using an off axis guider.  Working on that setup and will try for my next Galaxy target this spring. 

Imaged with Celestron 8" SCT at F6.3 (1290 mm focal length) using a Celestron focal reducer/field flattener, IDAS NGS1 light pollution filter, and full spectrum modified Nikon D5300. Total integration time of ~3 hours (109 subs at ISO200 x 120 sec). 

Pre/post-processing in PixInsight.   Images calibrated using Weighted Batch Pre-Processing (BPP) script using darks, flats, and flat darks . Registered and stacked using StarAlighment and Integration processes. Initial post-processing steps included: cropping and gradient removal with ABE.  Noise reduction using MLT, photmetric color calibration, SCNR, stretch using Generalzied Hyperbolic Stretch, HDR transformation, and local histogram transformation.

I spent quite a bit of time learning more about the Generalized Hypoerbolic Stretch (GHS) and using that tool for this image's processing.  One option that really helped my star and galaxy colors is the GHS color option that implements aspects of the arcsinh stretch.  The script also lets you blend images, my final version is a blend of a standard GHS streth and a GHS color stretch.  Highly recommend giving GHS a try in Pixinsight, see:  https://ghsastro.co.uk/