The narrowband UHC filter, like the O-III filter, isolates the two doubly ionized oxygen lines (496 and 501nm) in addition to the hydrogen-beta line (486nm) emitted by planetary and most emission nebulae.
This filter blocks low and high pressure mercury and sodium vapour lamplight and neon light whilst letting the rest of the visible spectrum through. Excellent for viewing all deep sky objects under the urban sky.
This UV/IR cut filter blocks UV and IR rays to maintain the color temperature you want, eliminating false colour fringes around bright stars. Offers a 99.9% light transmission rate for bright and clear images.
Standing for "City Light Suppression", the Explore Scientific 1.25" CLS Nebula Filter is not just for observing nebulous objects, as it lets a broader swathe of wavelengths through to the observer than either the OIII or UHC Explore Scientific filters do.
More versatile than the OIII filter, the Explore Scientific 1.25" UHC Nebula Filter will work on a broader range of nebulous objects, due to its dual peaks in transmissions on both broader OIII lines and Hydrogen wavelengths
For glare-reduction in observing the Moon the #905 Variable Polarizer includes two Polarizer filters mounted in a specially-machined cell. The #905 permits variable settings of the light transmission between 5% and 25%, to account for varying lunar surface brightness