Astronomik CLS Light Pollution Filter - 2" Round Mounted

  • Sale
  • Regular price $159.95
  • Astronomik CLS Light Pollution Filter - 2" Round Mounted

    • Sale
    • Regular price $159.95
    • ITEM #



    Astronomik CLS Light Pollution Filter - 2" Round Mounted

    Astronomik CLS Light Pollution Filter - 2" Round Unmounted

    The Astronomik CLS is an excellent filter for black & white and color imaging of nebulae, galaxies and star clusters with astronomical instruments of any size. By blocking the spectral lines of mercury and sodium-vapor lamps, and letting the largest part of the visible light and H-alpha emissions pass, the CLS filter will effectively block out most surrounding light pollution, eliminating that annoying orange glare.

    The filters are optimized for use with filter to aperture ratios of 1:3 to 1:15. By remaining within these aperture ratios, aberration and comma are eliminated.

    Astronomik CLS Light Pollution Filter - Transmission Information

    • 92% transmission at 486nm (H-beta)
    • 92% transmission at 496nm (OIII)
    • 92% transmission at 501nm (OIII)
    • 97% transmission at 656nm (H alpha)
    • Pass from 450 to 540nm and beyond 650nm


    • Parfocal with other Astronomik filters
    • Glass thickness: 1mm
    • Highly resistant against high humidity, scratches and aging effects
    • Diffraction limited, the filter will not reduce the optical performance of your telescope!
    • Astronomik filters are delivered in a high-quality, long lasting, filter box

    Additional Information

    Filter TypeCLS
    Free ShippingYes
    Peak Transmissionalpha
    Warranty10 Year Warranty

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    Questions & Answers

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    • How does this filter differ from the Astronomik CLS CCD Light Pollution Filter (Item # AK-CLSCCD-2)?

      The main difference is that the basic CLS filter does not block IR wavelengths, while the CLSCCD does. The CLSCCD also has higher maximum transmission (~98-99% vs ~92-95%) of key wavelengths as well as steeper cutoffs to reject light pollution a bit more

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