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Old 02-04-2011, 06:29 PM
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Paddy (Patrick)
Canis Minor

Paddy is offline
Join Date: Jun 2007
Location: Strangways, Vic
Posts: 2,210
Lovely sketch of a very beautiful OC, Orestis. Well done.

BTW I found that Scott Tannehill's fan modification for the GSO dob got rid of any secondary dew problems on mine. I found that I didn't need to change the mounting of the fan as the vibration was minimal - I only put the cover around the back of the scope with a gap for the fan inlet to push the air into the tube and stop it bouncing back off the primary and put the baffle a few cm above the primary to direct air over the primary. Neither mirror ever dewed again. I could feel the gentle flow of air out of the end of the OTA. It also meant the primary cooled down much quicker and the scrubbing of the boundary layer meant I could go to higher powers sooner.
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