Orders placed after 4PM on weekdays will not ship until the next business day. Orders placed after 11AM Fridays will not ship until the following Monday.
Faster shipping methods may be available; just upgrade during checkout.
*Some exclusions apply.
Enter new zip code to refresh estimated delivery time.
The original Lumicon Cassegrain Ultra High Contrast Rear Cell Filter is unbeatable for revealing nebulosity. This is achieved by passing three nebula emission lines-the two doubly ionized oxygen lines (496 and 501nm) and the H-beta line (486nm)-while blocking light-pollution and Sky Glow. The result is superb views of the Orion, Lagoon, Swan and other extended nebulae.
The Lumicon Cassegrain Ultra High Contrast Filter threads onto your telescope's SCT rear-cell, and presents male SCT threads for accessory attachment.
Lumicon knows that all sky viewing is not done under the best of weather conditions. 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.
Note: Recommended for telescopes 8" and larger in aperture
To ensure that your Lumicon filter remains the world's best, the strictest quality control standards are employed throughout the production process
Each Lumicon Ultra High Contrast Filter is individually inspected and proudly inscribed with the percentage of light transmittance of the OIII and H-beta emission lines
The 1.25" filters employ industry-standard 1.125" x 42 tpi threads (except for Questar/Brandon, which use a thread pattern unique to Questar). The 48 mm filters employ industry-standard 48 x 0.75 mm threading, which thread into 2" eyepieces. All larger filters use the given size with 0.75 mm pitch (e.g. a 72 mm Minus Violet filter has 72 x 0.75 mm threads)