Make a Quick and Easy Dew Shield that Really works!
If you have a utility knife, a tape measure, and $10 you can make the dew shield pictured above in no time. I bought the material at the local Home Depot. The material I used was a black flexible formica like countertop material. It is on large rolls and you buy it by the foot. Cost me about $4 for more than enough of it for a dew shield. Also pick up a roll of velcro tape and a can of flat black spray paint. Remove your corrector cover and take a measurement of the circumference of the ring the cover fits on. Add about 1" to this measurement for overlap. The length of the shield should be approximately the length of your optical tube (this is up to you but the longer it is the longer it will stave off dew). Mark the 2 measurements on the formica, try to use the natural curl it will have for the circumference but it will work either way. Using a flat straight edge cut the formica with a sharp utility knife. Put a piece of masking tape along the inside edge of one side, lengthwise (this is to keep paint off the area you will stick velcro to). Paint the inside of the formica with a couple thin coats of flat black spray paint. Don't get carried away and put it on too thick or it may start to warp. After the paint is dry remove the strip of masking tape and apply velcro down the length of the formica, one side on the inside and one side on the outside. Now curl the formica into a tube. Adjust the tube size with the velcro until it is a nice snug fit over the corrector ring. Put a small patch of the hook side of velcro on the top of your optical tube and another patch on the top of the dew shield. Now make a strap of the soft loop velcro by cutting 2 pieces and sticking them back to back. Attach the strap to the velcro patch on the dew shield and leave it there. Now you can just slip the shield on and push the strap down to hold it in place. Note that your dew shield may not seem to need any velcro to hold it in place, it will. After being out in the dew for a few hours it will swell up slightly and the fit will become looser and it will fall off without the strap.The reason for making the strap out of the soft stuff is so you can't accidentally scratch your corrector plate putting it on. I have found that even on the worst nights (and we get them here in Florida) it will keep me dew free for at least 4-5 hours. Note the tiny dew shield on my CCD guide scope, that is made in the same fashion, but using foam type drawer liner material (the kind you see lining the shelves in a Craftsman toolbox). The dew shield isn't overly heavy, in fact it actually helps balance out the rest of the accesories mounted on the back of the scope. If you own an SCT you definately need a dew shield. I originally was making this one to hold me over till I could order one, but it worked so well I kept it!
Tip Submitted by Emilio J. Robau : (Instead of painting the inside of mine I sprayed it with glue and applied black felt, it may be a bit heavier, but should help prolong dew free viewing due to it's thermal properties)