ALFOIIISG1

FOIIISG-1

Alpine Astronomical

This 1.25" 9nm O-III Super-G CMOS Filter from Alpine Astronomical is designed for observing and photographing planetary nebulae, supernova remnants, and many large emission nebulae. Its 9nm FWHM and CMOS-optimized coatings deliver high visual contrast against the sky background and a 97% transmission rate for the emission line at 500.7nm. The filter can be used photographically from f/1.8 to f/12 without passing any light of the H-beta line, making it ideal for areas with high light pollution. The mounted filter features a Reflex-Blocker hard coating, plano-optical polishing, and Life-Coat sealed edges.None Increased contrast, matched for typical CMOS quantum efficiency and s/n ratio Reflex-Blocker coatings 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 all around, with filter-lead-side-indicator in the form of a black frontside outer rim to eliminate any reflection due to light falling onto the edge of a filter Each filter coated individually, with sealed coating edge (not cut out of a larger plate with coatings left exposed) Life-Coat: hard coatings to enable a non-aging coating for life, even in a most adverse environment