1.Optolong UHC Introduction

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 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 (i.e. skyglow). Together with the highly transparent in main nebula emission lines at OIII(496nm and 500nm), H-beta (486nm), NII(654nm and 658nm), H-alpha(656nm) as well as SII(672nm), 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 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 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.

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.

List of Compatible Cameras with Optolong EOS-FF Clip-in Filter

2. UHC Spectrum for Reference

3. Optolong UHC Performance

I The Milky Way Hongkong, Cityscape shot by Vincent Cheng

II NGC2244 Rosette Nebula _by Dengyunwei

Using Optolong UHC filter

III You can see the Milky Way in Kunming City, image shot by Yule who used Optolong UHC.

See the compare.

Ⅳ M42 by Jxsky, Optolong UHC filter

V Compare iamge by astrophotographer Luocheng.

About Optolong

While Optolong is a relative newcomer to the astronomy industry, they are no strangers to optics and filters. Optolong is a division of Yulong Optics Company, a high tech company specializing in optical filter design and production. Their products include bandpass filters, flourescence filters, edge filters, longpass and shortpass filters, beam splitters, anti-reflection coatings, optical mirrors and, of course, astronomical filters.

Established in 1999 and based in Kunming City, China, Optolong/Yulong provides nearly 2000 types of optical filter coatings annually to customers worldwide in a wide variety of industries and applications.