Quote:
Originally Posted by Omaroo
Bojan - The CCD window through the front plate is now totally isolated from the cold finger by the cork. This should, in my mind anyway, prevent the front plate from gathering much ice, as such. The box is open oround the heatsink - to the air, so will be impossible to hermetically seal and fill with nitrogen.
Can I ask what you meant by " I have noticed that the cold finger is not exposed very much at all..."? What would you do?
Cheers
Chris
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What I meant is, cold finger is not present in the cavity where CCD is.
You may have a situation where the CCD is the coldest part in a cavity, and then you may have undesirable condensation and ice accumulation on the CCD window, if that cavity is not sealed and filled with dry gas..
In other (classical, like Coockbook camera) designs, people deliberately left cold finger uncovered, and as this is the coldest part, the ice accumulates on it and once all moisture is removed from the (sealed) cavity this way. CCD stays free of ice.
In my own design (I placed a picture in another thread some time ago), I followed that principle.
You can find it by searching
"Home made CCD astro-camera - my version" and in attached picture. (no it is still not finished.. but it will be shortly. However, it saw a first light
).
Anyway, you will see how it goes.. it may not be the problem after all