I know there were a bunch of these listed a while back, and then sold... but at that time I wasn't sure what I was going to do. Now I am looking for a 217 filter for my Orion, or perhaps an Inrad filter of similar bw. Anything out there for sale??? mathenyr at marietta.edu. Thanks. Ralph Matheny K8RYU 207 Gibbons Place Marietta Ohio 45750