Hi David
I made a dew shield for my C9.25 from closed cell foam - the kind of stuff used in camping mats for sleeping on. Their closed cell construction prevents them from soaking up moisture like a sponge, and it also appears to make them tough and tear resistant. Good foam/rubber outlets, such as Clark’s may also stock the closed cell mat too. Something in the 5 to 10mm thickness range would be ideal.
I chose the strategy of preventing dew rather than clearing it off after it had already formed. To this end, I use the
Kendrick dew heater system. Basically it is their standard controller unit with dew heater straps that plug into it, and then they fit around the SCT corrector, eyepiece(s) and finder scope to prevent dew build up in the first place.
Cheers
Dennis