The best all-purpose nebula filter on the market today, the Lumicon Cassegrain Deep Sky Filter blocks all high & low-pressure mercury and sodium vapor lamp light, neon lights and airglow, while transmitting the rest of the visible spectrum. The Cassegrain Deep Sky Filter threads onto your telescope’s SCT rear-cell, and presents male SCT threads for accessory attachment. The Cassegrain filter cell allows you to change eyepieces without threading/unthreading the filter, and is also easier to change-out than the standard 2″ filter cell with gloves on, for cold-weather observing.
Visually, the Deep Sky Filter enhances contrast of nebula under both light-polluted and dark skies. The Deep Sky Filter also passes infrared light, making it an excellent filter for photographing most deep space objects through light-polluted skies.
To ensure that your Lumicon filter remains the World’s Best, the strictest quality control standards are employed throughout the production process. Each Lumicon Deep Sky Filter is individually inspected and proudly inscribed with the percentage of light transmittance of the H-Alpha, H-Beta and OIII emission lines.