Celestron Color Eyepiece Filter Set #1 - #15 Yellow, #21 Orange, #80A Blue, and Polarizer

This Celestron 1.25" color filter set consists of the following four filters - #15 deep yellow, #21 orange, #80A medium blue, and a polarizing filter. Here are details on the individual filters:

#15 Deep Yellow
Recommended applications for this filter:
Moon - Improves contrast between lunar features of varying brilliance in scopes 6" and larger, especially when combined with a polarizer or neutral density filter. Venus - Somewhat helpful in revealing low-contrast banding in the thick Venusian cloud cover. Mars - Increases the contrast of polar caps, frost areas, low clouds, and dust storms against the ochre deserts. Also sharpens the boundaries of yellow dust clouds. Jupiter - Useful for darkening atmospheric currents containing low-hue blue tones and enhancing detail in small orange-red zonal features in the belts. Useful for studies of the polar regions. Saturn - Useful for darkening atmospheric currents containing low-hue blue tones and enhancing detail in orange-red zonal features in the belts. Improves the visibility of Cassini's Division in the rings. Neptune and Uranus - Useful for enhancing very subtle dusky features in scopes 10" and larger. Comets - Enhances the definition in comet tails.
67% transmission

#21 Orange
Recommended applications for this filter:
Moon - Very useful for improving contrast between lunar features in scopes 6" and larger, with or without polarizer. Mercury - Darkens terrestrial sky during daylight viewing to enhance rarely visible subtle surface albedo differences. Venus - Darkens terrestrial sky during daylight viewing to show the phases more clearly. Mars - Increases the contrast of polar caps, frost areas, low clouds, and dust storms against the ochre deserts. Also sharpens the boundaries of yellow dust clouds. Jupiter - Brings out structure in the belts and enhances festoons and polar regions. Saturn - Improves the structure of atmospheric bands and highlights blue-toned polar regions. Comets - Can be piggybacked with #38A filter to improve contrast of orange Sodium D lines in comet gas tails in scopes 10" and larger. Enhances the definition of comet heads and dust tails in 10" and larger scopes. Solar - Used to give correct color rendition of the Sun when using a Mylar solar filter.
46% transmission

#80A Medium Blue
Recommended applications for this filter:
Moon - Very useful as a contrast-enhancing lunar filter under dark sky conditions with scopes 6" and larger. Mercury - May improve observations of rarely visible dusky surface features at twilight, when the planet is near the horizon. Venus - Increases contrast of occasional faint dark shadings in upper Venusian clouds. Mars - Useful for enhancing the visibility of surface features and localized dust storms, clouds, and ice fogs with 8" or larger scopes, particularly during the still-unexplained phenomenon of violet clearing (when the Martian atmosphere - normally a bright, featureless disc in violet light due to the scattering of short wavelengths of light by the thin atmosphere - becomes transparent through a violet or blue filter, revealing large dark surface features). Jupiter - Primarily used for enhancing the boundaries between the reddish belts and adjacent bright zones in the upper atmosphere. Helpful in defining the Great Red Spot and festoons in the belts. Saturn - Brings out details in the belts, zones, and polar regions of the planetary disc. Comets - Brings out the best highlight definition in comet gas tails in 8" and larger scopes.
30% transmission

30% Transmission Polarizing Filter
This filter transmits 30% of the incident (reflected) light by blocking those light waves that are not vibrating parallel to its axis of polarization. It can be used as an irradiation- or glare-reducing filter for lunar and planetary work. Since lunar and planetary light is randomly polarized, rotating a single polarizing filter will not provide selective and variable glare reduction, as it will with polarized terrestrial light reflections from metal, glass, or water. Two polarizers, however, may be stacked together and rotated relative to each other to provide a variable density system with 5% to 30% light transmission. One polarizer may be stacked with color filters for lunar and planetary use where more glare reduction is needed without affecting the contrast enhancement. As with neutral density filters, it is helpful in splitting binary stars by reducing the glare and diffraction around the brighter star of a binary pair. The filter is also useful terrestrially with 1.25" eyepiece spotting scopes to reduce the glare off water, glass, etc., for birdwatching or nature studies.
30% transmission