Cleaning a Filter

Is it okay to clean a filter (color, moon, nebula & solar) the same way as an EP? Any comments and / or suggestions will be greatly appreciated. Thanks in advance, Paul

Hi Paul,

I use only distilled water which is available at most pharmacies with a few drops of Ajax dish washing liquid. If you substitute the soap it must not have any hand softeners or additives for your skin. I then add one container of 91% isopropyl alcohol. DO NOT use rubbing alcohol.

I pour out enough water from the gallon container to accommodate the alcohol and pour it all in the gallon container. I then use a coffee filter to strain my solution and rinse my cleaning bowl. Then I add some to the bowl again using the coffee filter. Add one drop of soap. I soak what ever I am cleaning in the bowl sometimes for quite a while and with a piece of white tee shirt material on the bottom of the bowl to prevent the bowl from contacting the glass being cleaned. Then I try to clean it with just the motion of lifting it in and out of the water. If that is not enough I use a small modeler's paint brush (with real animal hair) to very very gently try to remove whatever it is. If this does not work I let it soak again and if it does not come off the second time (90% of them do) it stays or soaks in a solution with a lot more soap and the process is repeated. The object here it to make them better not worst and realize 90% is better then ruined.

When they are clean I fill another bowl using the same method less the soap and use it for the final rinse. The alcohol helps the water to evaporate so there should be no need for any wiping. I have a space heater near by and that is what I use not paper or a cloth to dry the glass. Spotting should not occur if the object and rinse solution is clean.

Have fun and always work over a soft surface.

I have used this for all my telescope needs and it has worked every time. Cost is about two to three bucks.

Tom & John .... Thanks for the great suggestions. I will give them a try. Paul

Dust can be removed from most surfaces with an airbulb. For grease and other adherent materials I use Zeiss Lens Cleaner and white kleenex. There was a thread in the eyepiece section regarding cleaning eyepieces that applies if you would like a diverse set of opinions. Most of us do clean our equipment from time to time, but with care and not very often.

Nebula filters want a bit more care than colored glass filters.
Often the simple broad-band nebula filters have the multi-layer
dielectric surface exposed and can be more delicate than other
filters. Go easy wiping these.

Some of the narrow-band nebula filters have a second glass to
protect the multi-layer dielectric surface. Here you need
to be careful not to let the cleaning solution seep into the
air space. If you have this type, probably best to put the
solution on the wiper and shake off excess liquid, and not put
liquid directly on the filter.