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Astronomik CLS Light Pollution Filter 1.25" - CLS-1

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Astronomik 1.25" CLS Light Pollution Filter Highlights

  • Removes urban lighting caused orange glow
  • Shows more stars and nebula detail
  • Works best with telescopes that have a filter to telescope aperture ratio of f/3 to f/15
  • Mounted in a 1.25" cell
  • The Astronomik CLS Filter offers almost 100% transmission between 450 nm and 530 nm including the visual and h-alpha area of the spectrum
  • The multi-layer coatings on all Astronomik filters protect very well against scratching, aging, and humidity
  • Made in Germany, a country known for their high-quality optics!

More About the Astronomik 1.25" CLS Filter

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 f/3 to f/15. By staying within these aperture ratios, aberrations and coma are eliminated.

All Astronomik filters are parfocal with all other Astronomik filters. The Astronomik 1.25" CLS Light Pollution Filter has a thickness of a mere 1 mm. It has a high resistance to scratches as well as the effects of aging and high humidity. This filter is diffraction limited and will not lower your telescope's optical performance. Astronomik filters arrive in a superior quality, durable plastic storage container.

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