Quote:
Originally Posted by Paul Haese
Thanks Marc. SBIG think similarly, that the heater on the sensor window is either dislodged, not connect properly or not function properly. The heat is not so bad. We have been getting night temps at Clayton around the low to mid 20's for the last month or so. The delta on the camera is very good and it can hold -30C with only 55% power. The QSI on the other hand struggles a bit with the warmer weather.
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Fair enough. I forgot you're remote. You can just open and close the roof at will when it's cooler at night.
re-cycling I was mentioning the extreme temp differential because I had similar fogging issues with a QHY8 and always in summer. Every time it was because I had to power the camera off for some reason and then repower it afterwards. It would fog pretty much straight away. I reckon the sensor/cold finger goes back to ambient too rapidly which might be in the high 20s in summer so you get condensation on the cold finger then when cooled again the dew spot would always start at the center of the sensor which I assume is the bit that gets colder the last. Then the dew spot grows until it covers pretty much all the sensor. Looks like vignetting or a bad flat fielding. In the worst cases the edges of the sensor started icing up and I had icicles creeping towards the center like little branches. The QHY8 was not regulated. So it's all or nothing cooling wise. I had one similar issue with the QHY9 which has a separate chamber for the sensor and it's argon purged. Again cycling too fast in hot ambient temperature caused a dew spot in the middle of the sensor. Ramping up the cooling/warming sorted out the issue as if the air in the chamber needs enough time to catch up with the cold finger .
