I was out stargazing the other night and the corrector lens frosted up on me. I looked into dew shields and found a few options, but I was hoping to get some feedback before making the purchase. I live in Colorado, dew wasn't an issue for me this fall as it's rather dry here. We do get frosty in the winters.
The first option is just a plastic shield from Celestron with a velvet lined interior to prevent glare from external light sources. It's very basic. Will this prevent my corrector from frosting up on me in the winter?
The second option is the heater ring from Celestron, it runs at full amperage unless controlled. Instead of paying and additional $250 for the controller, I found the Astro Zap Pegasus for $90. I know it's just a manual controller. Do I need this to prevent frost or this overkill?