Does anyone use it to clean telescope optics? If so, what brand? Some are
said to contain propellants that can be detrimental. If you use one, advice
on where to obtain it would be appreciated.

Hi:

I use it all the time for corrector plates, cameras, and eyepieces. I don't
recommend it for first surface mirrors due to the possibility of blowing
propellant onto the surface of the mirror and damaging the coating.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
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