Astronomik UHC Photo

The Astronomik UHC filter stands out as the first choice for visual observation, offering enhanced contrast and detail in deep-sky objects that surpasses other filters on the market. With its Ultra High Contrast (UHC) design, the filter allows nearly 100% transmission of OIII and H-beta lines, effectively eliminating scattered light from various sources, including light pollution. This results in a significant enhancement of detail for gaseous and planetary nebulae against the sky background.

Designed for versatility, the Astronomik UHC filter is effective in both urban and dark sky conditions, improving contrast for emission nebulae and other celestial objects for medium to large telescopes. It dramatically increases the visibility and detail of objects that are otherwise faint or obscured.

The filter's application spans aperture ratios from 1:3 to 1:15, suitable for a wide range of telescopes. Compared to filters from other manufacturers, the Astronomik UHC filter excels in revealing more stars and finer details in celestial objects, maintaining the sharpness and optical quality expected from high-performance astronomical instruments.

The filter works by blocking emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, the majority of emissions from LED lamps and all lines of natural airglow, while allowing H-beta and OIII lines to pass through. This selective transmission enhances the contrast between the sky background and observed objects.

Additionally, the Astronomik UHC filter is recommended for observation of Jupiter's clouds and offers improved separation of double stars. 

In summary, the Astronomik UHC filter is indispensable for astronomers seeking to maximize visual clarity and contrast in deep-sky observation, making it an essential tool for all deep-sky observers alike.

Alternatives 

• For telescopes smaller than 5" (125mm), the Astronomik UHC-E filter with its wider pass band is more suitable.
• Telescopes with apertures exceeding 10" (250mm) may benefit from an Astronomik OIII visual filter as first filter.

Suitability of the Astronomik UHC filters

• Visual observation (dark skies): Very good, for telescopes of all aperture ratios
• Visual observation (urban skies): Very good, for telescopes from 4“ (100mm) aperture

Technical data

• Typical transmission of 95% at 486nm (H-beta)
• Typical transmission of 95% at 496nm and 501nm (OIII)
• Typical transmission of 95% at 656nm (H alpha)
• Transmission range: 480nm to 505nm and above 645nm 
• Full-Width-Half Maximum (FWHM): 25nm
• Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)
• Finely polished optical glass, free of any striae, residual stresses, and bubbles
• Extremely scratch-resistant and durable coating
• Completely resistant against high humidity and aging effects
• Astronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)
• Parfocal with other Astronomik filters
• Diffraction-limited
• Optimized spectral windows
• Delivered in a high-quality, long-lasting filter box

Due to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore effectively eliminated. 

All Astronomik filters are ideal for modern cameras, including both CMOS- and CCD-based models, ensuring you capture the best possible images with your equipment. Sharpness, contrast, and the absence of any reflections and halos are guaranteed. Even with bright stars in the field of view, nebulae and galaxies will be captured with the finest structures. The Astronomik MFR coating is designed for optimal performance across a wide range of focal ratios of the optics used.

Every Astronomik filter undergoes a rigorous quality control process before delivery. Additionally, each Astronomik Narrowband-Emissionline filter is measured using a high-end PerkinElmer Spectrophotometer to ensure it meets the specifications published on our website. On the back of each Narrowband-Emissionline filter box, you will find a label detailing the precise spectral data for that specific filter, including the maximum transmission and the recommended range of focal ratios.