Astronomik 31mm UHC Filter />Mounted in a Low Profile Non-Threaded Round Cell
The Astronomik UHC filter is for visual deep-sky observation. It lets almost 100% of the radiation from both O-III lines and the H-beta line pass through. A second bandpass for the H-alpha line ensures that this radiation also reaches the eye, and scattered light from other wavelength ranges is also filtered out. Due to the strong reduction of the sky background, gas and planetary nebulas are visible with an unexpected abundance of detail. Because of the high transmission, the UHC filter provides enough light to successfully observe deep-sky objects with smaller telescopes.
The filters are optimized for use with focal ratios of f/4 to f/15. Unlike other filters on the market, loss of transmission and color displacement with the Astronomik filter occurs only on telescopes with extremely fast focal ratios of f/3 on up. Compared to the UHC filters sold by other manufacturers, the Astronomik UHC filter shows you more stars and more details in nebulas, and because of the high quality of the glass, you will see stars as small pinpoints.
Now Mounted in Low Profile Non-Threaded Cell
Sometimes unmounted filters can be hard to handle. The smaller diameters, such as this 31 mm UHC filter, can be especially difficult to pick up and insert or remove from the filter wheel, and that can lead to possible damage as well as unwanted reflections from incorrectly installed filters. Astronomik has solved this problem by mounting their 31 mm and 36 mm filters in a low profile (3 mm) non-threaded cell. O-rings, washers, or spacers are no longer required to hold the filter in place, and because the cell is only 3 mm thick, it works well in all appropriately sized filter wheels. Mounted 31 mm and 36 mm Astronomik filters will also play nice with unmounted versions in the same carousel.
Astronomik filters are in a class by themselves when compared to other filters made by Japanese and US manufacturers. The coatings are completely sealed and insensitive to moisture. They do not change with the years, but keep their transmission characteristics indefinitely. The coatings are so hard that is it not possible to scratch them by mistake. You would have to rub them with sandpaper to get even the finest of scratches! Due to these outstanding characteristics, Astronomik gives them a 5 year guarantee. Each filter will be sent in a useful protective case.
Astronomik 31mm UHC Filter Features...
- Transmission of nearly 100% of O-III and H-beta
- Transmission of 96% of H alpha
- Entire blocking of annoying wavelengths
- Ideal all-round Deep Sky filter even for small telescopes
- Not sensitive to humidity or aging
- 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
- Cell thickness: 3 mm
- 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
Astronomik Product Number: UHC-31
- Additional Information
SKU AK-UHC-31 Manufacturer Astronomik Type of Filter Contrast Booster Filter Usage Visual Single or Set? Single Filter Filter Size 31mm Filter Shape Round Filter Mounted? Mounted Warranty 5 Year Warranty Peak Transmission 96% of H-Alpha; nearly 100% of O-III and H-Beta
- Included Items
- Astronomik UHC Filter - 31mm Round Mounted
- Protective Plastic Case
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