The new Baader UHC-L Ultra High Contrast filter is a dual-bandpass visual and photographic filter designed to block light pollution and increase the contrast of emission nebulae and cometary C2 emission lines. The high transmission results in a much brighter image than other UHC filters. The passbands centre around the OIII & H-alpha lines making this a wide dual-band filter without changing the star colours.
This new version is optimized to reject the main LED emissions in the blue part of the spectrum, as well as natural night sky glow and classical street lamps. It is also coated with the latest CMOS-optimized Reflex-Blocker coatings, so it blocks more off-band light than previous UHC models.
The UHC-L can be used visually as well as photographically, where it acts as a light pollution-blocking luminance filter, while cutting off the UV and IR ends of the spectrum. Additionally, the UHC-L is suitable for comet observation, as it passes the OIII line at 501nm as well as the two C2 lines at 511nm and 514nm, which are typical for the gas tails of most comets.
The optical surface is fine-optically polished so that there is no loss of sharpness at high magnifications, even when the filter is positioned far in front of the focal point. They can even be put in front of a binoviewer without introducing astigmatism.
Baader CMOS-Optimized filters - advantages
-
Very high contrast due to steep edges of the coating
-
Reflex-Blocker coatings to minimize reflections caused by correctors, reducers and other optical elements
-
Standardized thickness for maximum possible parfocality - less need to refocus due to different filter thicknesses
-
Blackened edges with front-side markings
- Each filter is individually fine-polished and coated with sealed coating edge, preventing moisture ingress
-
Life-Coat for hardness and age-resistance, making the filters able to withstand tougher conditions for longer
For more information on Baader's new generation of CMOS-optimized filters, check out this blog post!
