[Atmos (Colin)]

http://www.iceinspace.com.au/forum/s...d.php?t=137056

Above is a link to the O-III filter.

Below are a couple of moon filters:
http://www.bintel.com.au/Accessories...oductview.aspx
http://www.ozscopes.com.au/celestron...r-1-25-in.html

I don't think you need to be too selective when it comes to moon filters.