Astronomik UHC 2″ filter
If light pollution from nearby towns and villages is ruining your observing sessions - or you simply want to get the most out of every night under the stars - the Astronomik UHC 2″ filter is exactly what you need. This filter is designed to transmit light in the narrow emission bands typical of nebulae - primarily H-beta and the pair of OIII lines - while effectively blocking most of the interfering spectrum from sodium and mercury street lamps. The result is dramatically higher contrast when observing emission and planetary nebulae, both visually and in astrophotography.
Premium optics from a trusted German manufacturer
Astronomik is a German manufacturer with a reputation that needs little introduction in the astronomical community. UHC series filters are made from optical glass with multi-layer anti-reflection coatings that ensure transmittance of up to 97% at the transmitted wavelengths. This is a critical parameter - cheaper filters with inferior coatings can unnecessarily steal light exactly where you need it most. The aluminium cell is precision-machined so that the filter fits securely and precisely into the standard 2″ thread of eyepieces or telescope accessories, with no play or vibration.
How the UHC filter works
UHC (Ultra High Contrast) filters work on the principle of selective transmission - they pass only those spectral bands in which ionised nebula gas glows (primarily OIII at 496 and 501 nm and H-beta at 486 nm), while blocking continuous radiation from artificial lighting and natural airglow.
Compared to narrowband OIII filters, the UHC has a somewhat broader passband, which gives it the advantage of greater versatility - it works well on emission nebulae as well as on objects with less pronounced emission. Key transmission bands:
| Emission line |
Wavelength |
| OIII |
496 nm and 501 nm |
| H-beta |
486 nm |
Who is this filter for?
Visual observers
For visual observers using telescopes from 100 mm aperture and above, UHC filtration provides an immediate and visible improvement in contrast on nebulae such as the Cygnus, Orion, and Veil nebulae. You will notice the difference at first glance.
Astrophotographers
Photographers will appreciate that the filter suppresses light pollution even during long exposures, making it possible to capture quality images under less than ideal conditions. The filter is fully compatible with standard CCD, CMOS, and DSLR cameras and reduces the impact of light smog without requiring a switch to strictly narrowband filters.
Urban and suburban observers
The Astronomik UHC 2″ filter is the perfect choice for anyone observing from suburban or urban locations who still wants to see emission nebulae at their best. Thanks to the 2″ size, it is compatible with the vast majority of modern eyepieces and telescope accessories on the market.
Quality and longevity
Astronomik ranks among the world's leading manufacturers of astronomical filters. Every filter leaves the factory with certified spectral characteristics and passes strict quality control. The multi-layer coatings guarantee long service life and resistance to abrasion and moisture. Astronomik offers a complete range of filters from broadband to narrowband, so as your collection grows in the future, you will continue to benefit from proven and consistent optical quality. An investment in an Astronomik filter pays off - once purchased, it will serve you reliably for decades.
