This Astrodon Near IR-Luminance filter blocks below 700nm and transmits at least 97% of light above 700nm all the way to the limit of the Si detector.
There are two types of luminance filters: NIR-blocked (L) and unblocked (C = Clear). The "L" type is designed to match the spectral range of RGB filters. Some astronomers prefer this for color images because of the spectral matching. Others want all the photons possible. The "C" type adds about 40% more signal from the NIR (using a Kodak KAF3200ME detector, for example) to produce a deeper luminance image. Most object colors and emission lines lie within the Visible part of the spectrum.
