Orpington Astronomical Society

Astronomy => Technical => Topic started by: Rick on Nov 28, 2003, 19:15:00

Title: Dew problems
Post by: Rick on Nov 28, 2003, 19:15:00
Yesterday evening was bad for dew, at least earlier in the evening. Dew is a problem for two reasons. First, it forms on the optics and leaves you peering through fog. Second, it condenses all over the scope.

Condensation on the scope's body can be dried off with a towel. The tricky part is what to do when it condenses all over the optics. Condensation is distilled water, so, as long as it doesn't pick up dust from the air it should evaporate in time without leaving any marks. I try to avoid ever wiping the optics in any way, as cloth and tissue may well contain particles which will damage optical coatings. Instead I tend to leave my scopes to dry in a warm room after an evening's observing, preferably with the main exposed optic surface facing down.

Other tips, anyone?

[ This Message was edited by: Rick on 2003-11-28 11:17 ]
Title: Dew problems
Post by: Anonymous on Nov 28, 2003, 20:24:00
Try a hair drier to clear the optics, use on low heat and well away from the optical surface, Would not want to see you crack a lens.

Other options are dew heater's here are a couple of sites with details, thinking of having a go this winter.
http://www.astrosurf.com/benschop/DewRemov.htm
http://www.petevasey.btinternet.co.uk/DewHeat.htm
http://mysite.verizon.net/res0owmd/id1.html
http://webhome.idirect.com/~rsnow/scopeheater.html
Title: Dew problems
Post by: Whitters on Nov 28, 2003, 21:00:00
http://www.hfo.org.uk/Anti%20Dew/antidewingsystem.html#tapeprice
Title: Dew problems
Post by: Mike on Dec 01, 2003, 07:18:00
You can make dew heaters very easily.
Title: Dew problems
Post by: Whitters on Dec 02, 2003, 05:11:00
Go on then . a bit more explaination :smile:
Title: Dew problems
Post by: Ian on Dec 02, 2003, 05:18:00
go out and buy a newtonian.

OK, perhaps less that useful, but hey? what's a dew problem?

To be fair, my eyepieces got a severe case of condensation on Thursday night but that's because they'd sat in my shed and were at ambient. Other than the OTA, a little warming up does no harm. (if you burn your eye on your eyepiece, you've probably over done it...)
Title: Dew problems
Post by: Whitters on Dec 02, 2003, 16:23:00
LOL :grin: