Cloudy V filter

Affiliation
American Association of Variable Star Observers (AAVSO)
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

Affiliation
American Association of Variable Star Observers (AAVSO)
Cloudy filter cleaning?

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

Affiliation
American Association of Variable Star Observers (AAVSO)
Hazy V filter

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

Affiliation
American Association of Variable Star Observers (AAVSO)
Rouge source for small amount

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?

Affiliation
American Association of Variable Star Observers (AAVSO)
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."

 

 

Affiliation
American Association of Variable Star Observers (AAVSO)
I tried IPA

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