Celestron Light Pollution Imaging Filter for 11" RASA OTA

Purpose built for their 11" Rowe-Ackermann Schmidt Astrograph (RASA) Telescope, the Celestron Light Pollution Imaging Filter replaces the optical tube assembly's (OTA's) optical window and maintains its optical performance and neutral color balance, as no extra piece of glass is added to the fast optical system. By fitting onto the front, the light is filtered before entering the optical tube, maximizing usable light and eliminating the need for a rear filter, which can add length and weight to your astrophotography or astro-imaging rig.

The filter selectively removes unwanted light pollution�such as that from high- and low-pressure sodium-vapor streetlights, mercury-vapor streetlights, and natural airglow caused by oxygen in the atmosphere�while allowing more overall light transmission to pass through the optical path to the imaging sensor. By blocking targeted wavelengths, specific ones including 656nm H-?, 486nm H-?, 496nm and 501nm O-III, and 672nm SII emission lines from nebulae are highly transmitted, so emission nebulae won't be dimmed.

Made with Schott B270 glass, the filter's anti-reflection coatings maximize light transmission to bring out subtle color in nebulae, galaxies, and other faint deep-sky objects, while preventing star halos. Every filter is individually tested for light transmission, and a graph of test results for your specific filter is included for your reference.