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