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The Ultra High Contrast (UHC) broadband filter was developed to improve the visibility of a range of deep sky objects.
This is achieved by reducing the transmission of some of the wavelengths involved in light pollution. In particular, those produced by artificial lighting such as mercury vapour lamps. But also by the blocking the light from sodium vapour lamps and the unwanted 'sky glow' effect. As well as being highly transparent to the main nebula emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm) and SII (672nm), the filter is also suitable for improving contrast and detail, for both visual and photographic astronomy, away from rural areas with high levels of light pollution.
Main uses and performance
- Suitable for colour CCD cameras and unmodified DSLRs
- UHC with smaller bandwidth offers higher contrast than CLS, making it better suited for urban environments suffering from heavy light pollution.
- UHC lets a substantial part of the red spectrum through, permitting great photographs of astronomical objects such as the Orion Nebula (M42)
- Light pollution filters do not increase the brightness of astronomical objects, but do not just eliminate light pollution. They also often increase the contrast between nebulae and the night sky.
Quality Materials
- Brand-name glass from Germany as the substrate, 1.0mm thick
- Multilayer antireflective coating applied via electron beam physical vapour deposition and ion beam assisted deposition.
Quality finish
- Filter substrates optically polished on both sides down to 1/4 lambda and with under 30 arc seconds non-parallelism
- Polishing quality 60/40, in accordance with MIL-O-13830
- A uniform and accurate coating method which ensures both high transmission in the passbands and high optical density in the off-band ranges
Please note that this filter must never be used as the only solar filter!
This article is not available to customers in Germany.
