Alpine Astronomical Baader C2 Swan-Band CMOS Filter (15nm) - OIII Parallel (2" Eyepiece)

Alpine Astronomical FSWAN-2 Overview

This for 2" eyepiece from Alpine Astronomical is designed for the observation and photography of comets, specifically their gas tails. The filter passes the 511 and 514nm carbon emission lines, which dominate the spectrum of a comet s gas tail, but blocks the O III lines 501nm and below, eliminating stray light. It is also useful for differentiating comets with gas tails from those with dust tails. The filter features a Reflex-Blocker hard coating, which has been optically polished, and has Life-Coat sealed edges.

Baader CMOS-Optimized Filter Features

• Increased contrast
• Reflex-Blocker coatings for freedom from halos even under most adverse conditions concerning aux-optics
• FWHM on each filter category carefully designed to allow for 1:1:1 exposures, matched for typical CMOS quantum efficiency and s/n ratio
• 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 additionally 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