[erick (Eric)]

Hi Ingrid

Best you move your question into a different thread - start your own.

If you search there are many threads on filters on the Forum.

Here is some other reading:-

http://www.myastroshop.com.au/guides/filters.asp

http://sciastro.net/members/portia.p...use-of-filters

http://pages.sbcglobal.net/raycash/filters.htm

http://www.omegafiltersebuyer.com/servlet/StoreFront

Cheers
Eric