Filter,1.25", High Contrast

USD $60.00
1.25" Specialty blocking filter: transmits only 480-510nM. M28.4x0.6
UHC is a filter that blocks the visual spectrum except for wavelengths between 480nM and 510nM. Often called a Nebular or ALP (anti-light pollution) filter, this allow passage of ionized oxygen and hydrogen lines, but blocks light pollution reflectance from mercury and sodium vapor lamps. Threads into all 1.25" accessories.