Celestron Oxygen III Narrowband Filter - 2" Round Mounted - 93624 Tele Vue Eyepieces Explore Scientific 20mm 100 Degree

Explore Scientific 20mm 100 Degree Series Waterproof Telescope Eyepiece - 2" Features

Dioptrx likely has better multi-coatings than eyeglasses

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Remove rubber eyeguard to reveal bare eyeguard flange

Celestron Oxygen III Narrowband Filter - 2" Round Mounted - 93624 Tele Vue Eyepieces Explore Scientific 20mm 100 DegreeAbout 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,