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Dewed Telescope

Started by behenry, 08/17/2012 05:14AM
Posted 08/17/2012 05:14AM Opening Post
I finished my observatory early this Spring and greatly enjoy all the benefits it provides. I was wondering what to do with the scope if it dews up. Of course prevention is the best method but the other night I was tweaking the polar alignment when the corrector dewed up. I was done with the session and wondered about the best way to deal with the dew. I suppose I could put the heater strip on but that takes a while on a 10-inch Mak-Newt corrector. I ended up placing a cover over the uncapped scope and closed the observatory. I thought about some desiccant packs in the lens cover or the hair dryer treatment. Of course before the observatory I would just carry the scope inside and let it dry out. Any thoughts about covering a dewed scope uncapped and closing the observatory?

Bryan
Posted 08/17/2012 11:28AM #1
If you cover the scope with the dew still on it, you reduce the rate of evaporation a great deal. Letting some air get to it would be good. Although dew seems quite clean, it contains minerals, dust and a miriad of microbes.

My cleaning solution is nothing unique. Mix up a quart of 50/50 distilled water and isopropyl alcohol, then add exactly one smallish drop of dawn dishwashing liquid. Wet a fresh cottom ball with it and wipe very gently. never wipe twice with the same cotton ball. On a ten inch scope I'll easily go through half a bag of cotton balls in ten minutes. The idea is to remove microscopic debris from the corrector without scrubbing it in or otherwise damaging the protective coatings.
Thanks,
Steve
8)
Posted 09/07/2012 12:39PM #2
Bryan Henry said:

I finished my observatory early this Spring and greatly enjoy all the benefits it provides. I was wondering what to do with the scope if it dews up. Of course prevention is the best method but the other night I was tweaking the polar alignment when the corrector dewed up. I was done with the session and wondered about the best way to deal with the dew. I suppose I could put the heater strip on but that takes a while on a 10-inch Mak-Newt corrector. I ended up placing a cover over the uncapped scope and closed the observatory. I thought about some desiccant packs in the lens cover or the hair dryer treatment. Of course before the observatory I would just carry the scope inside and let it dry out. Any thoughts about covering a dewed scope uncapped and closing the observatory?

Bryan

Never cap a dewed up scope. That's how mold/mildew/fungus grow...

Uncle Rod

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Posted 09/07/2012 09:25PM #3
I do not have much experience with dew, but keep an old hair dryer out in the observatory just in case.

I would avoid any capping of a wet scope.

Alex
Posted 09/09/2012 08:43AM #4

I use a hair dryer at the end of a nights observing. Then turn on the heater strips. I never remove the heater strips just unplug them when using the scope. After use plug them back in and turn them on. I also use a permanant dedicated 5amp regulated power supply 24/7 365 days a year in my observatory. And never cap a dewed scope.
Cheap insurance for clean optics IMO.

Andy


Gene Roddenberry "took" television "into" outer space.