Astrodon 50mm Tru-Balance FWHM 6nm H-Alpha Filter Unmounted

The Astrodon Tru-Balance filter was designed with a 6 nm FWHM and a minimum of 85% throughput for telescopes => f/4. This filter is parfocal with all other Tru-Balance filters and will reject light to 0.001% transmittance outside the bandpass. We call that OD=5 out-of-band blocking, all at 1/4 wave (or better) propogated wavefront. This is a truly high quality astronomic filter for amateur imagers.