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Newtonian Condensation Control - SW 200PDS


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#1 Roy

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Posted 25 September 2014 - 01:59 PM

I stumbled on this method of keeping the mirrors free from condensation during imaging sessions largely by accident. The problem that I was trying to solve was how to prevent the build-up of moisture film on the mirrors when the scope is left standing between sessions.  The solution was to fill a muslin bag with a few hundred grams of self-indicating silica gel and place it in the recess behind the primary mirror, sealing it with a home made cap.  This works perfectly, but what I hadn't expected was that if it's left in place it keeps both mirrors free from condensation during and imaging session as well as during storage.  The gel needs to be warmed-up in a microwave every few days, depending on the amount of moisture absorbed, but that's the only inconvenience and at least it's a saving on heater tapes and a controller.  I do suspend a second bag from the upper end of the tube if the scope is being left unused for several days, which is obviously removed before imaging! 

 

Roy       


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Roy

 

200PDS; 102mm Mak; ST80; NEQ6

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#2 Neil

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Posted 26 September 2014 - 10:51 AM

Thats very good advice Roy,

 

I never cap my Mewlon during the night as it traps in the moisture which is obviously not recommended. Now that I have an obsy I'm going to invest in a dehumidifier to keep in dryer when closed up etc... This will hopefully keep the condensation and moisture under control for me. 

 

Indicating desiccant is also used in my dry box for the ccd camera to keep everything ship shape for imaging. You can buy sealed plastic boxes for photographic equipment online etc...

 

Clear Skies

 

 

 

Neil.