This has been a half marathon (a long way for me), not in terms of capture, but processing. Severe gradients were in danger of spoiling, what for me is, one of my better images. Gradients may have been due to the waxing first quarter moon, cloud dodging and/or internal reflections as a result of adding an IR cut filter in front of my RGB filters to try and improve star colours.

Captured in Envisage, pre-processing, stacking and alignment in Nebulosity were straightforward. As soon as I imported the integrated frames into Startools and stretched these, excessive gradients were apparent. I worked hard to remove these using crop and wipe, with limited success - there was always excessive noise in my final image.

I turned to my ‘trusted and tested’ solution - Penumbra v0.6, a small program written by George Morimosato specifically for stacking and aligning frames obtained using the Meade DSI series of cameras. A simple interface, belies the complex coding, which magically stacks, aligns and removes background gradients; in addition basic HDR brightening and sharpening tools provide a good starting image for further post processing. [https://neurohack.com/penumbra/Tutorial1.html]

The resulting L,R,G,B frames were then composed in Startools and a little further stretching performed with DPP, before contrast, further selective HDR brightening, sharpening and deconvolution to the galaxies. Default colour was good with a little saturation applied to enhance these, and the starburst in M82. Minimal noise reduction followed by ‘de-warping’ of stars at the edge of the field, and slight shrinking completed my processing... after several hours and multiple approaches!

As ever, I am open to suggestions as to how I can improve this further. For the time being I am just happy to have something to show for all the time and effort invested. There are so many renditions of these galaxies, that I’ll let you look there for more information on these interacting galaxies and their influence that led to the starburst in M82, perhaps a 100 million years ago. Awesome.