FLI Research Grade 65mm Square SII 8nm Filter
FLI's Research Grade 65mm Square H-Alpha Filter's are of the highest quality, made to the highest standards with the finest production methods. Each and every one is coated in a durable AR coating on both of the filter's surfaces, ensuring that they are highly durable to scratches and dents- with a scratch/dig resistance rating of 60/40. These coatings are of course applied with extreme, exacting precision to make sure they do not impair the filter's performance of their primary intended function. Transmitted wavefront is better than .25 wave/inch at 635nm. Research grade filters are 5 +/- 0.05mm, par focal +/- 0.2mm, (filters start par focal +/- 0.1mm per recipe). Parfocal to f/4.5.
This filter isolates Sulfur-II with a precision down to 8 nano meters. This particular Sulfur-II filter has a bandwidth of 8nm. Unmounted, this filter will fit into filter wheels made to accept 65mm filters.
Manufacturer Product Number: RG-65S-SII