Worrying issue with home made full aperture filter.

[Cosmic Geoff]

I made a full aperture solar filter of conventional design, using Baader Astrosolar film, for a 127mm Maksutov.  The filter was sandwiched between two pieces of cardboard stapled together, each with a 125mm hole, and securely glued on one side to a cardboard ring which fits over the telescope tube.

Afrer some use, I found that the filter was wrinkling and doming out as a result of the pistoning action and trapped air when pushed onto the OTA.  Not too worrying, till a gap appeared at one edge, allowing solar light through. 😲

On dismantling it, I found that the film was only pierced by one staple, and was otherwise free to slide.  I stuck the filter edges in place with some adhesive tape.

[johninderby]

When I have made my own solar filter I used two sided adhesive tape to stick the film in place. Used the tape on both pieces of cardboard. Film never moved at all. Might be worth taking your filter aoart again and using the two sided tape.

Edited August 10, 2020 by johninderby

[Peter Drew]

If home made,  make sure you've peeled off the protective film on the filter material.     🙂