Astronomik CLS Light Pollution Filter - 2" Round Mounted

Astronomik CLS Light Pollution Filter - 2" Round Mounted
Item # AK-CLS-2
  • The Astronomik CLS Filter is a high quality light pollution reduction filter.
  • This CLS filter is mounted in a 2" cell.
  • The Astronomik CLS Filterprovides nearly 100% transmission between 450nm and 530nm which includes the visual spectrum and h-alpha making it an excellent choice for both visual and photographic use.
  • The multi-layered coatings on all Astronomik filters protect amazingly well against scratching, aging, and humidity.
  • The Astronomik CLS Filter shows more stars and detail in nebulae.


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

Additional Information

Manufacturer Astronomik
Type of Filter Light Pollution Reduction
Filter Usage Imaging, Visual
Single or Set? Single Filter
Filter Size 2"
Filter Shape Round
Filter Mounted? Mounted
Warranty 10 Year Warranty
Peak Transmission 97% at H-alpha

Customer Reviews 1 item(s)

Excellant LPR
Seems this filter does it all. Great light pollution control. Brings out detail in everything you use it on from polluted skies.
Enhances the views on nebulae, galaxies and clusters.Dims the background but not the image
oes not dim the image
1= Houston, We Have a Problem & 5= It's Out of This World
Review by Brad in Phx / (Posted on 8/6/2007)
Included Items

Included Items

  • Astronomik CLS Light Pollution Filter - 2" Mounted
  • Plastic Case
Questions & Answers

Product Questions

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