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Hi Martin
I've never seen a definitive answer to the odd cross hatch pattern in images, and I've only experienced it once or twice and I believe it went away with more integration time (i.e. low signal so stretching the bejesus out of the master). I dont think at this stage faulty or frosty sensor is the likely culprit.
I think I'd read that its usually caused by incorrect debayer settings in stacking, or shot or dark current noise stacked from non dithered frames.
I'd suggest the following if you havent tried these yet:
You dont mention dithering or the use of dark frames. If you dont dither, try dark frames as part of your calibration set. I'd always recommend dithering btw. Personally I dither ~15px every sub, and use dark frames in calibration. Costs nothing and moar calibration frames are always good. Remember, you can leverage a dark library for around a year of imaging.
Just checking you are using offset 50 with gain 100? A low offset and stacking in a product like DSS that doesnt have pedestal subtraction routine may leave artifacts subject to the signal level.
I suspect it might be that you're not 'swamping' the read noise with your sub length. Assuming you're using the f5 newt in your sig, with 3nm filters in a bortle 8 3mins may not be enough. Granted I'm at f7 on my rig which is quite a bit slower but I never go under 10 min subs on the antlia 3nm at unity on the 2600, and even then my mean adu on an average sub on a reasonably faint target is 650-700 with the Ha. Given the bias mean adu on a 2600 at gain 100 is ~505adu theres not a lot of net signal in a single sub. Hard to see from your screenshots, but it does look like the hatching pattern is significantly less noticable in the high signal areas of your picture...
Going to 5 mins at f5 should be sufficient? That, and dithering at least 12-15px might be worth a try? Best of luck solving this! I'm sure you will!
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