Fri, 09/07/2018 - 15:30
I bought a V filter by Custom Scientific about 1.5 years ago. Unfortunately even if I do not live in a humid city the filter is now cloudy and I am unable to remove the haze with Acetone. The filter appears to have soft AR coating that I have most probably damaged during the cleaning process. What shall I do next? Shall I send it back to the manufacturer for servicing or can I try a sort of polishing by7 myself? Polishing will probably defintely destroy the AR coating. Is there any disadvantage in using a filter with no AR coating?
Thank you
Gianluca
Good question.I bought some used UBVRI filters and the B is a bit cloudy. Surely some of you experienced users have some tips. What is the best way to remove clouding?
Thanks, Randall
Here's a discussion of the problem:
https://www.aavso.org/cleaning-photometric-filters-0
I have used optical rouge for this problem with success. It gives the filter a bit longer lifespan, but eventually the haze comes back. Once it affects the internal surface (between the layers of glass) the filter is shot.
Phil
Phil, Thanks, good idea. I used rouge decades ago to polish a mirror I ground. Do you use it dry? What is a good source for optical grade rouge?
Do you know any glass pushers (mirror makers)? You only need a very tiny amount. Ask around. That's how I got mine.
Here's a quote from my post in that forum.
" Moisten the tip of your finger (I used distilled water), then pick up the smallest amount of rouge possible by just touching the moist finger to a small amount of rouge . Polish the hazy side gently with your fingertip. Remove the rouge with a cotton ball or Q-tip. I used medical cotton balls.
The extreme periphery of the filter near the cell didn't get completely clear because of the raised edge of the cell. A Q-tip might do a better job there, but I was worried about possibly dislodging some dirt hiding in the glass-cell junction that might cause a scratch."
99.9% IPA doesn't work either. 99.9% ETOH didn't work either. Friction with a lint-free vacuum cleaning cloth got some of it. The rouge sounds like a good idea. These things do come out of the mounting cells. Use an adjustable optic wrench, or buy one to fit. I think Custom Sci has a wrench. Thor Labs has them also.
I had a blue one go bad after 10 years. I just count on having the V go bad every year.Two years at most. I need to get them out and look at them every couple months.
Ray