Baader Planetarium O-III 1.25" 9nm Super-G CMOS Filter

Enhance your astronomical observations and photography with the O-III 1.25" 9nm Super-G CMOS Filter, specifically designed to capture the fluorescence of doubly ionised oxygen in gas nebulae, primarily in planetary nebulae and supernova remnants. This advanced filter, with a Full Width at Half Maximum (FWHM) of just 9 nm and CMOS-optimized coating technology, significantly darkens the sky background, effectively blocking stray light more efficiently than its 10 nm predecessor.

The narrower FWHM, however, is not the only improvement. The filter boasts superior blocking outside of the O III wavelength, steeper transmission slopes, and a broad plateau in the transmission range. With a transmission rate of 97% for the emission line at 500.7 nm, nearly all the light from the nebula is allowed to pass through the filter. This makes the Super-G filter an ideal choice for areas with high light pollution.

The 9 nm O-III filter is perfect for photographic use on all telescopes, especially when paired with a DSLR or an astronomical OSC color camera. It incorporates all the benefits of the CMOS-optimized Baader filters, including the Reflex-Blocker coating against reflections, plano-optical polishing, and the age-resistant Life-Coat coating. For monochrome cameras, we offer the even stronger Narrowband (6.5 nm) and Ultra-Narrowband (4 nm) filters, specifically adapted for different aperture ratios.

The Super-G filter, with the same thickness as the 1.25" Baader LRGB filters, serves as a "super G filter". In the transmission range of the standard green filter (490-580nm), there are no emission lines other than OIII; H-Beta at 486 nm is already covered by the RGB blue filter. Thus, using the 9 nm O-III filter instead of the standard RGB green filter results in a stronger emphasis on emission nebulae, while the stars appear fainter.

The Baader O-III Super-G filter incorporates all the advantages of the new generation of CMOS-optimized Baader filters. These include increased contrast, matched for typical CMOS quantum efficiency and signal-to-noise ratio, Reflex-Blocker coatings for maximum freedom from halos, identical filter thickness to existing standards for parfocality, and blackened edges all around to eliminate any reflection due to light falling onto the edge of a filter. Each filter is individually coated, with a sealed coating edge, and features the Life-Coat: hard coatings designed to ensure a non-aging coating for life, even in the most adverse environments.