After 2 attempts to capture M51 with my 86mm Apo I used this years galaxy season to attempt it with my EgdeHD 11, hoping for more detail - and improved processing skills.

M51 is a beautiful spiral galaxy 24 million lightyears away in Canis Venatici and 77 lightyears in diameter, interacting with its smaller neighbour NGC 5195.
The interaction of the two galaxies have created extensive tidal feautures of large plumes of gas reaching far out into space at about twice the diameter of the galaxy.
The galaxy also experiences some enhanced star formation activity which the Ha signal emphasized well.

Just below are 2 tiny galaxies to be seen of magnitude 15, IC 4277 and IC 4278, the latter one some incredible 232 million lightyears away (the farthest I have observed soo far)

Gatherering 10 hours of data took three nights over 3 weeks due to cloudy weather; L channel still under represented, so another night needed to complete.

Processing in PixInsight took up much longer, as nasty satellite trails demanded some more learning sessions on WBPPs sub processes of Cosmetic Correction and Adam Blocks tipps for lower than default sigma values in ImageIntegration, and the blue channel resisted proper registration until I discovered the toggle to allow for clustered sources. It also helped to add another full night of data and long flats of 2-10 secs...

Processing workflow:
- taking long flats with dimmed LED panel of 2-10secs per channel
- WBPP with altered parameters of allowing clustered sources in registration and sigma 2.0 in Integration
- cropping the master lights as the cemera had been on variuos angles across the sessions
- LinearFit alls channels to H as being the highest median
- GradientXpert of all LRGBH channels
- ChannelCombination RGB image and SPCC color calibration
- Integrating RGBH with CombineHaWithRGB scripts of Continuum Subtracted Ha
- BlurX and NoiseX on RGBH
- EZ SoftStretch of RGBH
- (tried ChannelCombination of L that was refined with BlurX and EZ SoftStretched, but data still not sufficient)
- CurvesTransformation of final composite with Rangemasks on core and plumes

Some snapshots along the way: