I have a like new Hydrogen Alpha filter made by Thousand Oaks. It is a 1.5 angstrom unit which shows prominances very nicely. The energy rejection filter I have is made to fit for a Takahashi FS-78, might work on the 76 model as well. Can be used on other scopes, just needs another ERF. for the end of the scope. Thousand Oaks makes all kinds.
I am asking $675 and that includes shipping in the CONUS. Used it at the Rockland astroparty and saw some great prominances aven a little surface detail.