Zhumell 1.25 inch Ultra High Contrast UHC Telescope Filter - ZHUL063-1
Optolong UHC Filter - 77mm Round Mounted - UHC-77 is no longer available.
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Optolong UHC Broadband Filter - 77mm
The Optolong 77mm Ultra High Contrast (UHC) will give you more enhanced contrast than typical CLS filters, however, it functions very similarly. This UHC filter virtually eliminates light pollution caused by both artificial and natural sources, delivering views of darker skies and increasing visibility of your favorite deep-sky objects. Skyglow, that is caused by neutral oxygen in the atmosphere and light from high and low-pressure sodium vapor lights and mercury vapor lamps, are suppressed significantly. This means that you can enjoy views or images from areas with heavy light pollution.
Optolong’s UHC filter lets desirable wavelengths pass at a peak transmission of 95%, including emission lines at OIII, H-Beta, NII, H-Alpha, and SII. This filter also has a substantial red passband, so objects like the Orion Nebula look awesome!
The Optolong UHC Filter has a diameter of 77mm is made with Schott glass that has been multi-coated with an ion-assisted deposition technology to ensure scratch resistance and stability on the central wavelength, or CWL. Each filter cell is made of lightweight, strong metal and is CNC machined, sand-blasted, black anodized, and then laser engraved.
Please Note: This 77mm thread-on filter is designed to work with lenses that have at least 100mm of focal length. When used with lenses shorter than 100mm, you may experience undesired effects due to gradation.
Quality Filter Materials:
- Schott B260 substrate material from Germany, 2.0mm thick
- CNC machined and black anodized aero-metal filter cell that is ultra-thin to provide largest clear aperture; Laser-engraved to prevent fading
- Multiple layers of anti-reflection non-cementing coatings applied via electron-beam gun evaporation with Ion-assisted deposition
Optolong Filter Manufacturing Processes and Parameters
- Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces
- Surface quality, according to MIL-O-13830, is 60/40
- 95% transmission of main nebula emission lines (i.e. H-alpha 656nm, OIII 496nm and 500nm, SII 672nm and H-beta 486nm)
- 0.1% transmission of off-band, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm)
- Optolong’s planetary rotation system is a homogenous and precise coating procedure that ensures both high transmission of pass-band and optical density of off-band
- Each filter comes with a plastic case with high pressure EVA case lining
Optolong is the Astronomy Filters division of Yulong Optics, an optical filter design and processing company out of Kunming, China that has provided filters for over 700 optical companies since 1999. All Optolong filters pass European Union RoHS requirements and have been certified by TUV Rheinland and Bureau Veritas.
- Optolong 77mm Round Mounted UHC Filter
- Filter Case
Dimensions & Specifications
Filter Size: 77 mm
Filter Type: Broadband Deep-Sky
Filter Shape: Round
Mounted or Unmounted: Mounted
We stand behind all the products we sell, and your satisfaction is our top priority. If you're not satisfied with the quality of your purchase, simply send the item back to us in its original packaging within 30 days of its delivery.
Return & Exchange Policy
At our site, returns are easy! You may return new, unused, and resalable items for a refund or exchange. Simply ensure that the item is returned in its original product packaging within 30 days of delivery.
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