Optolong UHC Ultra High Contrast Filter for Full Frame EOS Cameras

The Optolong UHC (Ultra High Contrast) Broadband Filter for Full Frame Canon EOS Cameras is designed to improve the visibility of various deepsky objects.

Compatible with Canon EOS Full Frame cameras.

By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lightings including mercury vapor lamps, both high & low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). Together with the highly transparent in main nebula emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm) as well as SII (672nm), the filter is suitable for enhancing the contrast and details for both visual and photographic purpose at sub-rural area with heavy light pollution. For slightly light polluted areas, instead of the UHC, we'd recommend Optolong's flagship product, the L-PRO that produces a continues spectrum of the night sky.

DUE TO PATENT RESTRICTIONS THIS ITEM IS NOT AVAILABLE TO CUSTOMERS WITH GERMAN ADDRESS. WE WILL NOT BE ABLE TO DISPATCH THIS ITEM TO GERMANY!

Main Use and Performance

Optolong UHC filters are suitable for color CCD cameras and unmodified DSLRs. UHC with narrower passband provides higher contrast than CLS, thus it is more suitable for urban environment where you suffer from severe light pollution. UHC has a substantial red passband and offer superb views for objects like the Orion Nebula (M42). Light pollution filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.

WARNING:

Optolong filters are not designed for solar observation. DO NOT LOOK AT THE SUN WITH ANY OPTOLONG FILTER as permanent eye damage will be the result.

Technical Data

• Schott substrate material
• Glass thickness 2.0 mm (1.25”/2”/36mm/77mm/82mm)  and 1.0 mm (Clip series)
• Surface Quality: 60/40 (Refer to MIL-O-13830)
• Fine-optically polished to ensure accurate 1/4 wavefront and < 30 seconds parallelism over both surfaces
• 95% transmission of main nebula emission lines (i.e. Ha 656nm, OIII 496nm&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). Transmission of 0.1% is equivalent to OD3 (Optical Density), and a high optical density value indicates very low transmission, and low optical density indicates high transmission.

Compatibility

This filter is compatible with Canon EOS 5D, 5D Mark II, 5D Mark III and 6D cameras

Filter Cell

• Ultra-thin filter cell minimise vignetting by maximising possible clear aperture (clear aperture is 26mm for 1.25” size and 45mm for 2” size)
• Aerometal Material
• Precise CNC Machining
• Sand Blasting Process
• Black Anodized Finish
• Extinction Treatment to Prevent Reflection
• Laser Engraving No Fading

Available Sizes

• Standard 1.25” & 2”
• Round 36mm Unmounted
• Round 77mm & 82mm Mounted
• Clip Filter Series (RESTRICTED TO GERMANY!) Please do not order Optolong Clip filters from Germany. We can sell only Astronomik UHC Clip filters to Germany.)

Compatibility

Canon EOS 6D Yes
Canon EOS 5D Yes
Canon EOS 5D MkII Yes
Canon EOS 5D MkIII Yes
Canon EOS 6D II No
Canon EOS 5D IV No

Packaging

• Plastic PP Case
• Imported High Pressure EVA Case Lining
• Silver Cardboard Box
• High Density Sponge Carton Lining

Optical Coating

• Multi-layer anti-reflection coating
• Non-cementing optical substrate coating
• Electron-beam gun evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change.
• Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band. (Please note, "planetary rotation system" is a type of optical coating process and does not refer to the astronomical system describing the motion of the planets in our solar system.)

The Major Emission Lines of Nebulae: H-α 656.3nm, H-β486.1nm, OIII 495.9nm, OIII 500.7nm 
The Major Emission Lines of Artificial Light Pollution: Hg 435.8nm, 546.1nm, 577nm, 578.1nm, Na 598nm, 589.6nm, 615.4nm, 616.1nm

Left image: with UHC filter    Right image: without filter