I have a 2 year old Daystar .42 angstrom Hydrogen-Alpha filter 102mm ERF for sale. This system features an optional 1 angstrom thermally controlled band adjustment for scientific studies and doppler work. In addition to finely detailed prominences, this filter shows amazing surface detail that can only be seen in very narrow band / expensive filters. University grade keeps focus uniform across FOV as opposed to having blurred areas at any given time on less expensive models that are still very impressive. This one is much better suited for photography and/or CCD work and doppler studies as noted above. Comes with very nice hard-shell water proof case, AP telecentric lens, 4" ERF, oven, and both 1" and 3" long 2" dia AP extentions. With exception of tiny barrel marks from nylon tipped set screws, all are in mint condition. See Cloudy Nights reviews and Daystar websites for details. I've just got too many other projects on the table (building an observatory 1st), and really need cash. As a result, I am puting this high ticket item up for sale. This filter system cost well over $6000 and still has 7 years left on warranty. I will sell for $5000 shipped, obo. Many thanks for considering!
FYI: I will post photos tonight! Thanks again!