[mental4astro (Alexander)]

Oh, and DO NOT USE A BLACK MATERIAL TO MAKE THE INSULATING DEWSHIELD FROM!

Black at night becomes a heat sink, sucking up all the heat from its surrounds. Black surfaces are the very first to cool and have dew form on them, and will actually be cooler than the ambient temperature. I've often seen frost form on black surfaces when every other non-black surface was not even wet with from dew.

In the case of an insulative perspective, a black wrap will actually suck the heat out of the OTA rather than keep it in, and in turn creating the very opposite situation what you are seeking.

The dewshield end of my Coreflute wrap has black felt inside it. On dewy nights the outside of the wrap that is around the black felt has dew start to form on it, while the rest of the wrap stay bone dry. Yes, there is not the heat of the OTA keeping it warm, but it is more the case here of the black felt actually sucking the heat out of the Coreflute around it and plunging its temperature than the lack of heat.

I also made an insulating dewshield out of an old yoga mat for my 8" SCT, and this was also very effective!