Beat city glow and moonlight: ultra-narrow 3.5nm FWHM windows isolate H-alpha (656.3 nm) and OIII (500.7 nm) so emission nebulae punch through severe light pollution and bright lunar phases.
True, measured performance: each filter ships with its own 0.1 nm-resolution spectrograph report—not a batch average—so you know the exact CWL, FWHM, and transmission you’re getting.
High transmission, low background: ~90–95% peak T on each passband with average OD6 blocking (~0.0001%) across unwanted wavelengths for maximum contrast and minimal gradients.
Star-friendly coatings: halo-suppression AR stack plus SiO₂ hard overcoat and built-in UV/IR blocking keep stars tight and reflections under control on refractors and fast astrographs.
Fast capture, flexible workflow: grab H-alpha + OIII simultaneously with OSC cameras to shorten integration windows; or use on mono as a high-SNR bi-color luminance source.
Built for modern rigs: 2" (M48×0.75) cell, 1.85 mm parfocal glass (≈30 arcsec parallelism); fits Altair magnetic holders, standard 2" filter wheels, and Altair Canon/Nikon lens-to-CMOS adapters.
Plays nicely with DSLRs & OSC: designed to pass through the Bayer matrix efficiently (works with modified and unmodified DSLRs) and pairs perfectly with sensitive OSC CMOS like Altair Hypercam.
Scale up your palette: combine with the DualBand SII-OIII or broader TriBand/QuadBand options to expand mapping flexibility while preserving narrowband contrast.
Specifications
Type: Dual-band ultra-narrowband line filter (H-alpha + OIII)
