Quote:
Originally Posted by Decimus
Hi Everyone
Here is a challenge - what caused the mottling on my subs of Eta Carinae a few weeks ago? (See below).
With rotten weather here in Tassie it wasn't until the very end of March that I managed to set up my gear (WO GT102 Apo refractor, the new ZWO ASI071 and Sky X Pro software. It was a warm and humid night (ambient=20 degrees C) and the camera struggled to reach the -20 C temperature I had set. I mucked around with gain and other settings trying to get focus right and I also reset the temperature to -15 and then -5 (as well as turning it off completely). This produced unusable darks as the settings were all over the place, including the gain. I wrote to ZWO who told me (twice) that the mottling on these subs was caused by dew. My mates down here disagree with this analysis. What do you think? The gray scale is just a snipped file of a sub; the colour one is part of the same sequence (60 secs).
Cheers,
Richard
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Looks like frost to me, perhaps dew. If its dew simply have a look and you'll see. If its frost you'll need to shine a bright torch at an angle on the sensor and you'll see it shining.
Greg.