Ever one to create a low cost solution
, I made a reflective cover for one of my FT scopes that used to "move" when it got hot.
I used a replacement cover for an ironing board. Do you have the same name for this device in the US? The fold-up narrow table that the clean laundry is pressed on.
The cover was quite inexpensive and one cover provided enough material for several scope sleeves. The base material is like a thin foam with a metallised backing.