Is this Condensation

[valleyman]

Was out Saturday night for the the first time in weeks due to the weather.

Had everything up and ready for Astro dusk, nice clear sky so spun round to NGC891 and started an auto run of 40/180 sec Lights.

Went back an hour later to check everything was Ok and found this (see pics) on the Preview. 

I had Dew shields on the front of the Williams and they were heated when I checked. Was using a Williams 81 Pro with a ZWO 533 MC Pro. Cooled to -10c

In the pictures you can see the condition gets worse as time goes by. 

Any suggestions would be most helpful.

regards

 

Pat

[Ibbo!]

Looks to me like ice on the cover slip or chip.

Maybe a change or recharge of the dessicant (if it has some) is needed.

I use a small dew band on my SX 694 to keep it free and turn said band off when imaging.

[valleyman]

I will try storing the Cams indoors as a precaution against the damp in the shed. That might help.

Could it have been caused by the CCD not being 100% secure on the scope.

 I noticed this morning when I went to investigate the problem that there was some very slight movement between the CCD and scope with one of the locking screws not complete tight. 

Edited December 14, 2020 by valleyman