I hope someone can help over an issue with my 4" achromatic refractor.
It has been stored for a couple of years under dustcovers in my detached garage which is fairly dry but unheated. Recently, I took it out and noticed that the was something like a film on the inside of the lens (between the elements?).
Can you give me any suggestions as to how to address this issue? I am reluctant to try to remove the lens to try to clean the inside in case it affects the alignment.
Also, any suggestions for cleaning the optics in eyepieces which have become somewhat dirty/dusty?