The moon filters enhance lunar viewing by cutting down on the Moon’s bright glare, improving contrast and making faint details easier to observe. This Moon Filter Set contains all the filters you will ever need to observe the Moon during its various phases. The set allows you to choose the best filter to use with different eyepiece and telescope combinations. Use the darkest filter with larger aperture telescopes and lower magnification eyepieces. Use the lighter filters with smaller telescopes and higher magnification eyepieces. This kit is essential for those looking to take the next step in exploring their telescope’s full lunar capability, or for seasoned lunar observers who use a variety of telescopes and eyepieces to observe the Moon.

Neutral Density Filters

The kit includes three neutral density (ND) filters: ND96-0.9 13% T, ND96-0.6 25% T, and ND96-0.3 50% T. These filters dim the entire visual spectrum from 400-700nm equally. The ND96-0.9 filter transmits 13% of the incoming light, the ND96-0.6 transmits 25% and the ND96-0.3 transmits 50%. They do not impart any color to the Moon, but reduce lunar brightness. With several ND filters to choose from, you can find just the right level of light transmission for the Moon depending on its phase, the aperture of your telescope, and the magnification of your eyepiece. ND filters can also be used reduce the glare from Venus to better see its crescent phases, and to help dim bright daytime views when using a telescope terrestrially.

Moon and Sky Glow Filter

The kit also has a moon and sky glow filter which selectively reduces light transmission at different wavelengths and greatly improves contrast for observing subtle lunar features. This filter imparts a very light purple color to the Moon. For those in light-polluted skies, the Moon & Sky Glow filter provides some contrast enhancement when viewing deep sky objects due to the filter blocking some wavelengths associated with common forms of light pollution, like low-pressure sodium (LPS) street lights. Here is the transmission graph for the moon and sky glow filter.

Housing

Each filter is housed in an aluminum cell, providing a rigid, durable frame for the filter glass. The filters thread onto Celestron 1.25-inch eyepieces and most other 1.25-inch eyepieces with a standard filter thread. The filters have threads on the top and bottom to stack with other filters for even lighter filtration options.