The UHC (Ultra High Contrast) broadband filter is designed to improve the visibility of various deepsky objects.

The UHC (Ultra High Contrast) broadband filter is designed to improve the visibility of various deepsky objects. By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lights including mercury vapor lamps, both high and low pressure sodium vapor lights, and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).

Together with the highly transparent in main nebula emission lines at OIII (496 nm and 500 nm), H-beta (486 nm), NII (654 nm and 658 nm), H-alpha (656 nm), as well as SII (672 nm), the filter is suitable for enhancing the contrast and details for both visual and photographic purpose at sub-rural areas with heavy light pollution.

Main Use and Performance

• Suitable for color CCD cameras and unmodified DSLRs
• The UHC filter has a narrower pass-band which provides higher contrast than the CLS filter, making it is more suitable for urban environments where there is severe light pollution.
• The UHC filter has a substantial red pass-band which offers superb views for objects like the Orion Nebula (M42).
• Light pollution filters do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.