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glend
04-05-2022, 10:31 AM
This is a good time of year to check on the dessicant used in your cooled astro camera. Any high level of humidity in the sensor chamber of a cooled camera is likely to result in chamber window fogging or ice crystal formation, with image impacts.
While different camera manufacturers take different approaches to maintain a dry sensor environment, some even use different approaches within their own product line. The well regarded ASI1600MM-C, at one time used dessicant pills sitting on pads in the sensor chamber, later versions moved to a ventilated tube which held the dessicant and which screwed into the chamber.
A couple of points about dessicant pills, they will over time degrade and turn to powder, this powder can coat glass and sensor surfaces in the chamber, with a fine dust. So an annual check up is a good idea.
When opening up the sensor chamber, you need to carefully inspect any O-ring seals around dessicant tube holder, front cover glass, etc. Any cracks in these seals can allow moisture into the chamber. Cameras that employ chamber glass heaters can cause cracking of seals.
I would recommend using a dry gas purge of the sensor chamber, when reassembling and inserting new dessicant. Dry gas, such as Argon, is easy to find (Bunnings sell canisters in the welding equipment area (you will need a valve for flow control and maybe a length of plastic tubing). I used Argon purges on my ASI1600, and on my DSLR Cold Finger builds, and know it works, provided you do it correctly.
Always use new dessicant, from a properly sealed package. I do not recommend trying to dry dessicant, as that process can generate dusting of the dessicant, which then flakes off in the chamber.
Caveat: Some cameras may not be owner servicable, and please check with your manufacturer before you open it up.

JA
04-05-2022, 10:43 AM
All good points Glen. Thx for the reminder. :thumbsup:
More work to do:D

Best
JA

AdamJL
04-05-2022, 10:46 AM
Great PSA, thanks, Glen!

Startrek
04-05-2022, 07:30 PM
Thanks Glen
I’ve already cleaned and fitted new desiccant tablets in my 2600MC , so ready to test this wonky Star issue on Friday and Saturday nights ( clear in Sydney)
Martin