Red filters (#25) are useful for observing Mars, increasing contrast between light and dark areas and improving surface details.
1.25" Vernonscope Mounted Glass Filters feature 1" clear-aperture optical glass. Numbers are engraved on the mounting to correspond with those of Kodak Wratten series. The mountings are edge-knurled and threaded to fit the bases of BRANDON oculars and DAKIN Barlows. Vernonscope Mounted Glass Filters cut glare, provide superior contrast, improve definition and reduce eye fatigue.