dew prevention

fizzy123 · Post by **fizzy123** » Sat Jul 03, 2004 8:04 pm

Does anyone know how to handle dew other than to use dew shades. I heard people use a series of resistors and a 9v battery to create heat to fight due, how to do it? :idea: :roll: I read the Weasner ETX site today and they claim that using a hair dryer is a bad idea as one guy's ep crack due to thermal stress, how true is it?

:?

anat · Post by **anat** » Sat Jul 03, 2004 8:24 pm

You can find how to make a dew heater from the following links:
http://www.seds.org/billa/dp/dewpower.html
http://www.mindspring.com/~jeffpo/dealwdew.htm
http://www3.sympatico.ca/mark.kaye/dewheat.htm
http://webhome.idirect.com/~rsnow/resister.html

Post by **Airconvent** » Sun Jul 04, 2004 12:03 am

A more convenient method (also more expensive) is to use heat packs. you buy them at those camping and winter clothing stores. I normally buy those with adhesives, so I don't need to fumble with rubber bands and scotch tape.

Another idea occured to me...I wonder if it would be practical to use a small piece of red hot charcoal below your scope. That should keep the ambience warm enough not to form dew. Only issues are :
1. weather the smoke will get to your optics
2. how to control so it does not become too hot
3. how not to accidently step on it

rich

Post by **acc** » Sun Jul 04, 2004 12:29 am

I have made a dew heater from resistors before and its rather easily done with a bit of time and patience. The trouble actually lies with having to bring batteries to the field and having wires hanging all over the scope. Eventually reverted to using heat packs. Convenient, guaranteed to work, and fuss free.