I purchased this spotting scope several years ago primarily for another of my passions - birds! However this scope is excellent for astronomy! The filter was made by a friend of mine from California. He had some extra filter material and offered to make one for my scope. The filter material was developed by the Baader Planetarium in Germany. It's official name is Baader Astro-Solar Safety Film. It is inexpensive and produces VERY good images! For more information on this film and availability, check out the September 2000 issue of Sky and Telescope Magazine (p.63). You can also contact us at the observatory. BTW, whenever I use this instrument in this way, I am struck by its "international" nature. The scope is from Austria, the tripod (Manfrotto) is from Italy, and the filter is made of German material. It's a small world after all.