Astronomik UHC 31mm

The Astronomik UHC is THE filter for visual observing.

You will enjoy using your Astronomik UHC filter because you will see more stars and more details in deep-sky-objects compared to using filters from all other manufacturers.

The Astronomik UHC (Ultra High Contrast) filter allows the transmission of nearly 100% of the radiation from both O-III and the H beta lines. Though the second window for the H-alpha-line is not intended for visual observing, it is important, if the filter is used with an electronic device. All annoying, scattered light from other wavelength sources, including local artificial light pollution, is reliably filtered out. With this strong blocking of the sky background an unexpected wealth of detail becomes visible for gas nebulae and planetary nebulae.

Main use

Astronomik UHC filters’ astounding high light transmission brings better views of deep-sky-objects even to small telescopes! The high transmission of our optical glass filters means that enough light is available to allow successful visual observations with telescopes beginning at 2" (50mm) aperture. Our Astronomik filters are optimized for use with telescope focal length f / ratios of f/4 to f/15. Transmission losses and chromatic distortions, which arise with other filters, only occur with Astronomik filters when extremely bright aperture ratios of 1:2 and more come into play. Another major advantage of our Astronomik UHC filter is the high optical quality of the filter glass. When using Astronomik UHC filters you will quickly notice the same needle-sharp stars which you are familiar with from your astronomical instrument without any filter!

Suitability

• Visual observation (dark skies): Very good, for telescopes of all apertures and high exit pupil
• Visual observation (urban skies): Very good, for telescopes from 100 mm aperture
• Film photography: Reasonable, but very long exposure time
• CCD photography: Good, when used with an additional IR-block-filter
• DSLR photography (original): Good, colour balance shifted but contrast enhanced
• DSLR photography (astro modified): Very good, colour balance is near perfect
• DSLR photography (MC modified): Good, when used with an additional IR-block-filter
• Webcam / Video (Planets): Unsuitable
• Webcam / Video (Deep Sky): Good, if light pollution is a big problem

Technical Data

• typ. 95% transmission at 486nm (H-beta)
• typ. 95% transmission at 496nm (O III)
• typ. 95% transmission at 501nm (O III)
• typ. 95% transmission at 656nm (H alpha)
• optimum position of transmission for telescopes with focal ratios from f/10 to f/3.5
• Entire Blocking of annoying wavelengths
• Ideal All-round Deep Sky filter even for small telescopes
• Not sensitive to humidity or aging
• Scratch-resistant!
• Excellent carrier material. The optical performance of your telescope is not reduced by the filter in any way.
• Parfocal with other Astronomik filters
• Glass thickness: 1mm
• Completely resistant against high humidity, scratches and aging effects
• Diffraction limited, the filter will not reduce the optical performance of your telescope!
• Astronomik filters are delivered in a high-quality, long-lasting filter box