Oxygen III / "oxygen" narrow-band filter 1.25 " / 496 and 501nm. The result is an extreme contrast between the black sky background and the weak photons of the Oiii light, which for detailed views, among other things, the veil, ring, dumbbell, crescent moon and Orion fog is needed. Each filter has an ultra-hard, vacuum-coated coating that was carefully developed to block the entire visual spectrum of 400 to 700 Nm. This surrounds the unnatural colored halos, the light stars that are with OII filters less sophisticated coating technology are common, eliminated.
