Nightsky 2" CLS Light Pollution Filter

The Nightsky 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.

• 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 Nightsky 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!
• Nightsky filters are delivered in a high-quality, long lasting, filter box