I have 2 full aperature glass solar filters. 1 for my C8 by Orion and 1 for my ETX90 (90mm Mak) by 1000 Oaks.
I've noticed after doing a solar observation, about 20-25 minutes the glass on the filters are just a bit warm and when I remove them there is ever so slightly a bit of warm near the correctors.
My question is: does any one think that this "slight warm area" could eventually damage the secondary mirror aluminum coatings and effect any glue that holds them in place?
Michael Boschat ( AAVSO colde = BMF )
Halifax Center - Royal Astronomical Society of Canada