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Optolong City Light Supression / Light Pollution Reduction CLS Filter - 1.25"

5.0 (1 Reviews) Read Reviews Write Review
Brand Optolong
Part Number Q1CL000403Y
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Product Info

Manufacturer Description

A. About Optolong's CLS FIlter

The Optolong CLS (City Light Suppression) filter is a broadband light pollution reduction filter that 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.
  • Suitable for color CCD cameras and unmodified DSLRs.
  • CLS has a wider passband than a UHC filter and is thus preferred when observing under mild to moderate light pollution from rural or suburban areas.

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

  • 1.25" astronomy filter with standard M28.5x0.6 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 26mm.
  • 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.

Reviews

5.0 (Based on 1 Reviews) 100% of reviewers recommended this product.
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    1. Guest

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      User Notes:
      Review by Evan S.
      1517106708
      Jan 27, 2018

      5.0 Fantastic Service

      Pros:

      Cons:

      Comments:

      Tom really was patient with a newbie astrophotographer, helped me identify the adapters I needed and got them out next day. Highly recommended!

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

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