This 50.4mm Round Baader H-alpha Narrowband Filter from Alpine Astronomical is a 6.5nm FWHM filter recommended for optical systems from f/10 to f/3.5. It features a Reflex-Blocker hard coating, which has been plane optically polished, and has Life-Coat sealed edges. It is equally suitable for modern CMOS sensors as well as older CCD camera technologies.
- Reflex-Blocker coating for freedom from halos, even under most adverse conditions concerning aux-optics
- Identical filter thickness to existing standards, with utmost care for parfocality
- Blackened edges with filter-lead side-indicator in the form of a black frontside outer rim to eliminate reflection due to light falling onto the edge of a filter
- Each filter is individually coated, with sealed coating edge (not cut out of a larger plate with coatings left exposed)
- Life-Coat evermore hard coatings are non-aging for life - even in adverse environments