UHC Light Pollution filter

UHC Light Pollution filter

  • Multi-layers 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
  • Ultra-thin filter cell minimize vignetting by maximize possible clear aperture (clear aperture is 26mm for 1.25”)
  • Aerometal Material, Precise CNC Machining, Sand Blasting Process, Black Anodized Finish, Extinction Treatment to Prevent Reflection, Laser Engraving No Fading.

DESCRIPTION:

The UHC (Ultra High Contrast) broadband filter is designed to improve the visibility of various deep sky objects. 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. sky glow).

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.

APPLICATION:

  • 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.

Size

Standard 1.25” & 2” | Round 77mm & 82mm mounted | Round 36mm Unmounted | Clip Filter Series

Note : This filter is not designed for sun observation. DO NOT LOOK AT THE SUN WITH THIS FILTER. You would be BLIND if you fail to observe the warning.

Note: For Solar observation use high quality solar film ie BAADER Solar film or Solar filter along with this filter.

 

  • Schott substrate material
  • Thickness 2.0 mm (1.25”/2”/36mm/77mm/82mm)
  • Thickness 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 the both surfaces
  • 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). 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.