Celestron Oxygen III Narrowband Filter - 2" Round Mounted - 93624 GPS Blackened lens edges and internal

Blackened lens edges and internal anti-reflection threads tweak the last bit of contrast for maximum image detail

Substrates are free of striae and plane-parallel polished to within 30 seconds of arc

Save money on batteries

or combinations with simpler interference filters

Celestron Oxygen III Narrowband Filter - 2" Round Mounted - 93624 GPS Blackened lens edges and internalAbout 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,