Optolong UHC Filter 1.25" - Light Pollution Filter for Nebulae

Optolong UHC Filter 1.25" - Light Pollution Filter for Nebulae

The UHC (Ultra High Contrast) broadband filter is designed to improve the visibility of various deep-sky objects. By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lightings including mercury vapor lamps, both high & low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (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 photograghic purpose at sub-rural area with heavy light pollution.

Main Use and Performance

Suitable for color CCD/CMOS cameras and unmodified DSLRs

UHC with narrower passband provides higher contrast than CLS. Thus it is more suitable for urban environment where you suffer from severe light pollution.

UHC has a substantial red passband and offer superb views for objects like the Orion Nebula (M42)

Light pollution filter do not increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, but not by brightening the nebula.

WARNING: the filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.

Which side of the filter needs to face towards the telescope?

Optolong has a good explanation on their page with a check on unmounted filters. With mounted filters, it´s easy. The side with the external thread must face the camera.

Link to iOptron page: Should Optolong filters be installed in a certain orientation? (external link)
You can download the generated PDF from our own server.