H-alpha/OIII/SII CMOS Ultra-Highspeed Filter 1.25"

In-line filters with 3.5 and 4 nanometer half-widths , recommended for optical systems from f/3.4 to f/2.3

H-alpha filter: This narrowband nebula filter only lets through red light with a wavelength of 656 nanometers, which is the line in which HII regions (hydrogen nebulae) are seen.

Filter OIII: The narrowband nebula filter only lets through light at 500 nanometers, which is the line where doubly ionized oxygen atoms shine, such as planetary nebulae and supernova remnants.

SII filter: The narrowband filter only lets through light from ionized sulfur atoms at 672 nanometers, which is the line at which many planetary nebulae, emission nebulae, and supernova remnants glow.

The CMOS-optimized filters Baader's are characterized by

• greater contrast
• narrowest widths at half-height (FWHM)
• Reflex-Blocker™ coatings , for maximum insensitivity to retroreflection from nearby auxiliary optics, even in the most adverse conditions
• Carefully designed FWHM for each filter category to allow 1:1:1 exposures, tuned to the quantum efficiency and signal-to-noise ratio typical of CMOS
• Filter thickness identical to existing standards, with extreme care regarding homofocality
• blackened edges all around, with a black outer rim on the front of the filter to additionally prevent any reflection of light incident on the filter edge
• each filter polished and individually coated with fine optics , with sealed coating edge (NOT cut from a larger plate with exposed coating edges)
• Life-Coat™ : Even tougher coatings to enable an aging-resistant coating for an unlimited lifespan, even in the harshest environments.

This new generation of CMOS-optimized filters is designed to become the new standard in the amateur astronomy sector.