Celestron Oxygen III Narrowband Filter - 2" Round Mounted - 93624 GPS If the filter is not

If the filter is not adjusted precisely to the H-alpha wavelength

Save money on batteries

TeleVue 12mm Delos Eyepiece - 1

or combinations with simpler interference filters

Celestron Oxygen III Narrowband Filter - 2" Round Mounted - 93624 GPS If the filter is notAbout the Celestron Oxygen III Narrowband Filter 2" The Celestron OIII Narrowband Telescope Filter isolates just the two doubly ionized oxygen lines (496 and 501nm 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,