SBIG STL11000 CCD Fog issue

I was testing an STL11000 newly acquired, it was really humid when started. It was working fine (focus, framing etc) when cooling down to -15 (default temperature). It was then cooled down to -30 for imaging, during which I saw something weird, I think is fog on CCD window (probably outside).

So does anyone have any experience/suggestion to avoid this in SGPro? I saw some suggestions to slowly cool down CCD, but I am not sure what is the setting for 11000.


Move someplace less humid :laughing:? Any time you get something below the dew point and there is a lot of moisture in the air the chance for fog/dew is pretty likely.

I would recommend using some sort of desiccant plug in your scope and also in your CCD. If you can keep the moisture out of the system it will go a long way to preventing due forming on the CCD window. The rate at which you cool it down doesn’t matter. You can also try using a dew heater in front of the CCD to try and keep the air in that region a little warmer.


I have experienced fogging of my STL a few times. I am in a VERY humid environment! This has only occurred when I left the camera mounted in the observatory during periods of especially humid weather.
What has worked for me is removing the camera from the observatory and storing it in a desiccant-packed camera bag while not in use, stored inside my home. Furthermore, I use desiccant packs in the OTA behind the corrective lenses in my iDK with an end cap. This prevents moisture laden air from filling the cavity between the lenses and the camera sensor window. My problem was having humid air trapped in the camera body and in the closed cavity between the camera and the lenses. Needless to say, your situation may be quite different than mine. I cool my STL only to minus 20C, winter and summer to make this annoyance less likely.

There is another point. IIRC, early STLs did not have a heat strip for the CCD window? Not sure about that. Later models did. Mine does. AFAIK, the only way you could determine that would be an email to SBIG with the serial # of your camera.

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