Celestron 93624 Narrowband Oxygen III 2" Filter - Isolates Oxygen Lines Emitted by Planetary and Emission Nebulae, Eliminates Un-natural Coloured Halos Surrounding Bright Stars, Black

• EXTREME CONTRAST: The 1-1/4" OIII narrowband filter isolates just the two doubly-ionized oxygen lines (496 and 501nm lines) emitted by planetary and emission nebulae.
• BLOCKS THE LIGHT SPECTRUM: Eliminates un-natural coloured halos surrounding bright stars.
• DETAILED VIEWS: Contrast between the black sky background and the faint photons of OIII light provides detailed views of the Veil, Ring, Dumbbell, Crescent and Orion nebulae, among other objects.
• CAREFULLY DESIGNED COATING: Each filter has an ultra hard, vacuum-deposited coating designed to block all of the visual spectrum ranging from 400 to 700nm.
• WEIGHT & DIMENSIONS: 1.0 pound | 3.0 L x 1.0 H x 3.0 W (inches).

The 2" OIII narrowband filter isolates just the two doubly-ionized oxygen lines (496 and 501 nm 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 to 700 nm This eliminates the un-natural colored halos surrounding bright stars common with O III filters of less sophisticated coating technology.