Help with PixInsight processing of OSC + L-eNhance files

[andefeldt]

The other night I captured 65x300s frames of M51 using my ZWO 294MC Pro camera with the Optolong L-eNhance filter (to reduce LP). However, I'm not sure how to pre- and post-process the frames in PixInsight (VNG or SuperPixel demosaic method) - if it's the latter, than how to proceed from there. Also, I'm experiencing heavy vignetting and noise in the final image.

I tried the SuperPixel way and then tried stacking the SuperPixel (and then aligned) frames, but that gave me an error saying that zero or low signal was found in some of the frames!
Using the VNG debayer mode I didn't get this error.

I then tried extracting the R, G and B channels from the aligned frames. I then wanted to stack the R then G and then B frames to produce a Master_R, Master_G and Master_B frame. That worked for G and B, but the R failed due to zero or low signal.

Also, no matter how I end up stacking the frames, I end up with a master frame with a great amount of noise and vignetting, eventhough I've used 100 dark flats, 100 flats and 50 dark frames (300s frames with same temperature as light frames, -25°C) - I don't use Bias frames. It seems a bit like the vignetting from my flat frames either isn't subtracted or is subtracted twice, thus creating a new vignet?

I've also shot M51 using a standard UV/IR filter and that ended up with the same result concerning noise and vignetting.

I've previously shot M33, M42 and Barnard 33 with the UV/IR filter (same settings as M51) and I didn't experience any problems with noise or vignetting. Only difference from then and now is the PixInsight version (installed the latest version).

Anybody with some advise and tips? Maybe and idea or two about what I've done wrong?

My pre-processing workflow with the standard VNG debayer:

• Dark integration
• Dark-Flat integration
• Flat calibration with MasterDarkFlat as darks (no BIAS used) - no calibration and optimize (I've tried optimizing with the exact same result)
• Flat integration
• Light calibration with MasterDark (no calibration) and no optimization and MasterFlat
• Cosmetic Correction with Auto Detect hot and cold (aiming for roughly 3000 pixels in both)
• Debayer (RGGB with VNG method)
• Star alignment
• Light integration
• (Drizzle integration)

I've added a link to a stacked file (VNG demosaic method). Maybe one of you guys can take a look at it?

M51 on Dropbox

Thanks!
Anders

Edited March 23, 2020 by andefeldt

[jimjam11]

Have you tried using the weighted batch preprocessing script? You dump your files into the appropriate windows, tell it you are working with cfa images, disable dark optimisation and it should do everything for you.

 

Edit:

The file you posted is pretty good:

It had a strong colour cast probably as a result of the filter but this can be reduced with ABE, Photometric Colour Cal and SCNR.

The workflow I followed is based on the Warren Keller Pixinsight book.

Edited March 27, 2020 by jimjam11
Added screenshot