I posted this on another forum but I would welcome any comments from the members here. The image below is a heavily cropped single 600sec sub of IC5146 which is one of 9 that I took to test out the ZWO Off Axis Guiding of my new Edge HD 8". To the right of centre is a patch of what appears to be rough chroma 'noise?'. (It can be seen better if the image is enlarged) I wonder if anyone can tell me what the likely to be the cause is. My poor embryo processing skills or a hardware issue? The camera is a ZWO294 cooled to -20deg. The problem also appears on the stack of the nine calibrated subs. I should add that no such issue appears on all my shorter durations subs to date. Any comment would be welcome. Thanks - John
Test 3.jpg
Hi John,
The camera may get dew when cooling down. You can try cool your camera step by step, like cool down to 10℃ first, then cool down to 0℃, at last cool down to -20℃. And wait for about 3-5 minutes between each step.
Thank you for the response. I tried the suggestion last night and it did seem to be a solution. Many thanks again. - John
