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dewcap in hi-res imaging

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#1 astrobobbo

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Posted 10 November 2012 - 03:48 PM

Hi,I am imaging from a very humid area and I often have to stop my observations due to the moisture that collects on the mirror of the telescope after only 30 minutes!
Would the use of a dewcap heater reduce the resolution of the telescope due to the warm air generated just on the telescope aperture?
Ciao

#2 Freddy WILLEMS

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Posted 20 November 2012 - 12:59 PM

I use a hairdryer !

#3 ToxMan

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Posted 20 November 2012 - 01:04 PM

Newtonian? Dobsonian? Open truss? Or do you mean the corrector plate on a Schmidt Cassegrain?

#4 JMac85X

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Posted 20 November 2012 - 01:41 PM

I bought an astrozap dewshield that has a heater in the base where you wrap it around the scope. Cost me $125 and an additional $130 for the heating control. Takes up a lot of power though, using my celestron 17ah powertank will last 4 hours at most with the dew heater on but it works great. I never tried the hairdryer technique before because I'm scared I might crack the lens and I hear you have to do it repeatedly. If you use an SCT you won't be sorry to buy an astrozap dewshield and on the nights its not that cold or humid you still can use the dewshield and not the heater.

#5 zAmbonii

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Posted 20 November 2012 - 01:52 PM

I was kinda worried about a heater strip running and how it affected the final images. It had been cold recently, < 32F. and I just went ahead and ran my heater strip full bore. For my 8" I really can't say that it had any affect on the final images.

See the images in this thread and this thread. To see what it looked like when the heater strip was on. I have a 12V 1.5A wall wart that I have hooked up to the strip...no heater control. I also have a separate dew shield that I also use.






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