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Optolong Ultra High Contrast UHC Nebula Filter - 2"

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1. PRODUCT DESCRIPTION

 

A. About Optolong's UHC FIlter

The Optolong UHC (Ultra High Contrast) broadband filter is designed to improve the visibility of various deep sky objects. It does this by:

  • Selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lighting (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)).
  • Being highly transparent to the main nebula emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha(656nm) as well as SII (672nm).

B. Main Uses and Performance

  • Suitable for enhancing the contrast and details for both visual and photograghic purpose at urban and suburban areas with heavy light pollution.
  • Suitable for color CCD cameras and unmodified DSLRs.
  • UHC has a narrower passband and thus provides higher contrast than a CLS (CIty Light Pollution / Light Pollution Reduction) filter. Thus it is more suitable for urban environments where you suffer from severe light pollution.
  • UHC has a substantial red passband and offer superb views of objects like the Orion Nebula (M42).

C. Spectral Curve Transmission Characteristics

  • 95% transmission of main nebula emission lines:
    • H-beta 486.1nm, OIII 495.9nm and 500.7nm, H-alpha 656.3nm, and SII 672nm.
  • 0.1% transmission of major transmission lines of artificial light pollution:

    • Hg (Mercury) at 435.8nm, 546.1nm, 577nm, and 578.1nm.
    • Na (Sodium) at 598nm, 589.6nm, 615.4nm, and 616.1nm.

D. Technical Specifications

  • Both surfaces are fine optically polished, accurate to 1/4 wavelength or better, and parallel to within 30 seconds or arc.
  • 2mm thick Schott B270 optical glass substrate material.
  • Very high surface quality of 60/40 or better (US Military Spec MIL-O-13830).

E. Optical Coating Specifications

  • Multi layer anti-reflection coated.
  • 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) so that there is no deviation due to temperature changes during use.
  • Precise and homogeneous coatings ensure high values of desired passband and blocking of unwanted offband.
  • Every single filter is tested and passed by Optolong before shipping to dealers.

F. Other

  • 2" astronomy filter with standard M48.5x0.75 male filter thread (no female thread, so it cannot be stacked with other filters).
  • Ultra-thin filter cell to minimize vignetting; clear optical aperture of 45mm.
  • Precision CNC-machined metal filter cell with sand blasted black anodized finish, anti-reflection treatment, and laser engraving.
  • High quality protective plastic storage case.

WARNING: Optolong filters are not designed for direct solar observation. NEVER use these filters for observing the Sun, or permanent eye and equipment damage will result.

 
 

Note: Occasionally, the product you receive might have a slightly different cosmetic appearance or labeling than what is shown. This can often change from batch to batch according to the whims of the manufacturer. However, you will always receive a brand new, original product as described above.

Description copyright: Agena AstroProducts - Reproduction without permission prohibited.

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