The dark blue or violet filters (#47) are useful when observing Venus to increase contrast. It will help detect clouds on Mars and enhance the polar caps. On Juiter, it darkens the brown belts.
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.