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Optolong City Light Supression / Light Pollution Reduction CLS-CCD Filter - 2"

Our Price: $159.00
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In stock (1 Available)
Ships by Next Business Day
Our Product ID: OFIL-OL-CLS-CCD-2in
Manufacturer SKU: Q1CL000404Y-02
Item Can Ship: Worldwide
Optolong City Light Supression / Light Pollution Reduction CLS-CCD Filter

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  • Optolong City Light Supression / Light Pollution Reduction CLS-CCD Filter
  • Optolong City Light Supression / Light Pollution Reduction CLS-CCD Filter - Representative Transmission Curve

Product Details

A. About Optolong's CLS-CCD FIlter

The Optolong CLS-CCD (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

  • CLS-CCD is the same as the CLS filter with one important distinction - it also blocks out infrared wavelengths (700-1100nm) so a separate IR cut-off filter is not required for imaging applications.
  • Suitable for enhancing the contrast and details for both visual and photograghic purpose.
  • Suitable for color CCD cameras and modified DSLRs for astrophotography.
  • Works well on most emission nebulae, planetary nebulae and supernova remnants. Should provide noticeable boost in contrast and visibility of fainter outer detail.
  • CLS-CCD 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.
  • It also blocks out infrared wavelengths (700-1100nm) so a separate IR cut-off filter is not required for imaging applications.

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 M48x0.75 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.

Additional Information

About Optolong

While Optolong is a relative newcomer to the astronomy industry, they are no strangers to optics and filters. Optolong is a division of Yulong Optics Company, a high tech company specializing in optical filter design and production. Their products include bandpass filters, flourescence filters, edge filters, longpass and shortpass filters, beam splitters, anti-reflection coatings, optical mirrors and, of course, astronomical filters.

Established in 1999 and based in Kunming City, China, Optolong/Yulong provides nearly 2000 types of optical filter coatings annually to customers worldwide in a wide variety of industries and applications. We invite you to learn more about Optolong/Yulong, their products, facilities, and processes by viewing the short video below:



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