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Astronomik CLS Light Pollution Filter 2" - CLS-2

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SKU: ASF-CLS-2

Astronomik 2" CLS Light Pollution Filter Highlights


  • Eliminates orange glow generated by urban lighting
  • Displays more stars and detail in nebulae
  • Optimized for telescopes with a filter to telescope aperture ratio of 1:3 to 1:15
  • 2" cell-mounted round filter
  • The Astronomik CLS Filter provides nearly 100% transmission between 450 nm and 530 nm which includes the visual and h-alpha portion of the spectrum
  • All Astronomik filters feature multi-layer coatings for superior protection against scratching, aging and humidity
  • Made in Germany, a country renowned for their optical quality!


More About the Astronomik 2" CLS Filter


The Astronomik CLS filter is an excellent option for color as well as black & white imaging of deep sky phenomena such as nebulae, galaxies and star clusters with astronomical equipment of any size. Mercury and sodium-vapor spectral lines are blocked, allowing the largest part of visible light and H-alpha emissions to pass, the CLS filter efficiently shuts out the majority of surrounding light pollution, eradicating that irritating orange glare. Optimized for use with filter to aperture ratios between 1:3 and 1:15. Aberrations and coma are done away with by keeping within these aperture ratios.

Astronomik filters are parfocal with other Astronomik filters. The Astronomik 2" CLS Light Pollution Filter has a thickness of only 1 mm. It is highly resistant to scratches and aging effects, as well as high humidity. Diffraction limited, the filter will not reduce the optical performance of your telescope! Astronomik filters include a high-quality, long lasting, plastic storage box.

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