The 1.25" Oxygen III Narrowband Filter from Celestron yields high transmissivity by blocking unwanted longer wavelengths of light, giving higher contrast to your observation and photographic experiences. By isolating just the two 496 & 501nm doubly-ionised oxygen lines emitted by planetary and emission nebulae, while blocking the rest of the overall spectrum of light. The result is extreme contrast between the black sky background and the faint photons of OIII light needed for detailed views of the Veil, Ring, Dumbbell, Crescent and Orion nebulae among other objects.
Each filter has an ultra hard, vacuum-deposited coating carefully designed to block all of the visual spectrum ranging from 400-700nm, eliminating the unnatural coloured halos surrounding bright stars common with less sophisticated O III filters.
