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Astronomik CLS-CCD Light Pollution Filter - 31 mm Round - CLSCCD-31

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SKU: ASF-CLSCCD-31

Astronomik CLS CCD Light Pollution Filter - 31 mm


  • Eliminates the resulting orange glare from urban light pollution by permitting the largest section of visible light and H-alpha emissions to pass while obstructing the spectral lines of mercury and sodium-vapor
  • The Astronomik CLS-CCD Filter shows additional star and nebula detail
  • The Astronomik CLS CCD Light Pollution Filter is a great choice for deep sky observing with telescopes or photo lenses of any aperture with f/3 and above focal ratios, as well as for DSLR, CCD, and black & white film photography
  • Allows close to 100% transmission from 450 nm to 530 nm which encompasses the visible light and h-alpha portions of the spectrum
  • Like all Astronomik filters, the 31 mm CLS-CCD has multi-layer coatings to protect against scratching, aging and high humidity
  • Made in Germany, a country noted for producing high quality optics!


More About the Astronomik 31 mm CLS-CCD Filter


DSLR Cameras have been remodeled for astronomical use, making them suitable for use with the CLS-CCD Filter in an extremely light-polluted environment. This filter highlights the contrast between the background and your selected object. It also has a wider transmission curve compared to UHC filters, transmitting more light to render stars that are less dimmed. The Astronomik CLS-CCD Filter has been optimized to simultaneously intercept as much spurious light as possible while providing the best performance for approved wavelengths.

The Astronomik CLS-CCD Filter intercepts unwanted mercury and sodium-vapor spectral lines while allowing the desirable visible light and H-alpha emissions to pass. This enables the CLS-CCD Filter to block out most of the encompassing light pollution, doing away with that bothersome orange glare. Great for DSLR, CCD, black & white film photography, and deep sky viewing, this filter works best with lenses of all apertures that have f/3 and above focal ratios.

Alternative uses for the Astronomik CLS-CCD Light Pollution Filter include easier Double Star resolution, and emission line data color imaging in the Luminance channel. As with all Astronomik filters, the CLS-CCD is parfocal with all other filters made by Astronomik. It is highly resistant to scratching, aging, and high humidity, and has a thickness of only 1 mm. This filter is also diffraction limited so you won't experience any drop off in your telescope's optical performance. Like all Astronomik filters, the CLS-CCD comes with a high-quality, long-lasting plastic storage case.

Transmission Specifications:


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