Celestron - Skylight filter (for SCTs)

For Schmidt-Cassegrains
If you were to use only one filter, Celestron’s Skylight
Filter/Dust Seal would be your most versatile choice. This general purpose, Wratten #1A filter
improves color saturation and balance, increases visual and photographic contrast, helps to
decrease glare in lunar and planetary observing, and penetrates atmospheric haze. It’s also an
inexpensive way to protect your investment in quality optics. This filter threads onto the rear
cell of your Celestron C5, C8, C9 1/4, C11 or C14 telescope to serve as an effective dust seal.
By leaving the Skylight Filter/Dust Seal on when removing or attaching other visual accessories,
you prevent dust and other atmospheric contaminants from entering the rear of your telescope.
Needless to say, it’s much easier to clean a dusty filter than a dusty primary mirror, secondary
mirror and corrector plate.
The Skylight Filter/Dust Seal must be threaded onto the rear
cell of the instrument before any other accessory is installed. The female end attaches to the
rear cell of the C5, C8 and C9 1/4 telescopes and the reducer plate of the C11 and C14
telescopes. All additional accessories mount onto the exterior/male threads.