| This Orion 1.25" dielectric eyepiece filter is designed to enhance surface and atmospheric detail on Mars. It can be used to good effect on Mars any time the planet is visible.
Most of the red, orange, or green filters recommended for observing Mars are made of ordinary dyed glass. Each passes only a broad swath of a single color, blocking all other colors, for a brute-force enhancement of one specific type of Martian feature or another. The Orion Mars filter is a more sophisticated dual band multiple-layer interference filter. Its ion beam deposition produces hard, stable coatings that resist changes due to temperature and humidity. The use of dielectric coatings, rather than dyed glass, gives high light transmission and better blocking of unwanted wavelengths. This yields higher contrast images and a more natural color spectrum.
Its multiple-layer dielectric coatings transmit the violet/blue wavelengths below 505nm and the orange/red wavelengths above 615nm wavelengths where Martian detail is rich. At the same time the coatings block the overbearing yellow/green wavelengths between 515nm and 615nm that can wash out surface detail. Polar icecaps appear more sharply defined, and landscape shading differences are nicely resolved. Polar hazes and cloud cover become visible. The effect is to enhance detail on the Martian surface while preserving the natural color of the polar caps and rest of the surface.
This multicolor approach provides a more natural view of Mars and a more realistic contrast enhancement than the broad brute-force approach of a dyed-glass color filter that turns the planet varying shades of a single unnatural color.
The filter's high transmission makes it effective even in small telescopes. The filter’s aluminum cell is precision machined with standard 1.25" threads that will thread into the chrome barrel of virtually any 1.25" eyepiece. The filter is supplied in a protective plastic case.
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