Glossary | Telescope accessories | General | Series | UHC
UHC filters increase contrast by suppressing disruptive light sources.
A UHC filter suppresses the illumination of the background sky caused by artificial light. By contrast, the wavelengths primarily emitted by nebular celestial objects are allowed to pass through.
The effect for the observer is a significant increase in contrast. The use of a UHC filter is not only advisable in light-polluted areas. Contrast is increased even under dark skies.