Thanks.
The filter is an un mounted 2 inch diameter Baader filter, gold on one side, pinkish red on the other. It was a prototype they gave to me for using some of my images on their site here
http://www.baader-planetarium.de/zub...lter.htm#uhc-s
I tried shooting the Horsehead and was a bit dissapointed, I think the Horsehead gives off not just H Alpha light but some H Beta as well?
Eta Carina really does well with a H A filter though.
Scott