The Orion 1.25" Mars Observation Telescope Filters enhances contrast of virtually all surface features. Dielectric coatings transmit violet/blue (< 505nm) and orange/red (> 615nm) wavelengths where detail is rich, while blocking overbearing yellow/green (515nm-615nm) wavelengths. Polar icecaps appear more sharply defined and differences in landscape shading are nicely resolved. Polar hazes and cloud cover become visible.
The filter's high transmission makes it effective even in small telescopes. The Blue #82A filter really "pops" the polar icecaps and nicely highlights polar hoods and clouds. The Orange #21 filter sharpens visibility of dark surface markings and polar regions. Surface dust storms become easily visible.