We are having a problem with our scopes on cold nights. (-10F is about average here.) One poorly aimed breath means that the eyepiece lens fogs. We have to remove the lens and keep it under our arms to warm up to clear it.
The scopes are wrapped with heating tapes which does seem to keep the large lens from fogging/steaming up. It is the eyepiece lenses that we are having issues with.
I searched Orion & Celestron's websites, but they just offer heating tapes which we already have. I am concerned that frequently wiping the lens free of moisture, even with a soft cloth, could eventually scratch the lens.
Does anyone have a solution?