Looks like the issue was similar but very subtle in some of my other pictures. The biases came out no where near as bad in the case of my helix picture but it looks as though there's less noise on the ones with no bias / darks applied.
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Originally Posted by LewisM
I have had this happen previously.
Try a few different settings. Set drizzle on (2x or 3x). Align channels in the output. Try a median kappa clip of 2.00 / 50 iterations for ALL subs (light, dark, flat, bias). Try AHD debayer or Super Pixel (though not sure if this works with DSLR RAW etc).
It looks to me like a debayer issue - adjust the bayer matrix transformation settings under RAW/FITS DDP settings menu.
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It's not a de-bayer issue as that would result first and foremost with a messed up colour scheme. That is actually ok. I use predominantly ADH and only ever use drizzle on small objects (drizzle has little to do with stacking and lots to do with light frame supersampling).
Quote:
Originally Posted by Jon
Could be a number of things:
1) The obvious first: are the darks and biases taken with the same ISO, duration, and (broadly) temperature as the lights?
2) you don't mention flats: is that because there aren't any, or they processed fine? If the latter, then I would think you mt have light leaking in when you took your darks and biases. I had this when light was getting in the viewfinder, with similar results. The darks *looked* ok until I stretched them.
3) uncheck the "set black point to zero" box in the settings menu. I have no idea why this might work, but it did for me when I had a similar issue.
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1) Yes, yes and yes. Using a QHY10. Darks and Lights are taken at 300seconds. Temperature is -20degC in all cases.
2) No flats. I rotated the camera during the imaging session resulting in flats that do more harm than good. Light leaking in darks and biases does sound plausible. I may re-do them, especially the biases.
3) Sounds like a good setting to try, I won't get a chance till wednesday but I'll give it a go then.