Astronomik Filters CLS Canon EOS M Clip filter (52907)

The Astronomik CLS is an affordable filter designed for visual observation, black-and-white photography, and CCD imaging of nebulae, galaxies, and star clusters. It is compatible with astronomical instruments of any size. Since 2008, the filters have been redesigned to eliminate halos and unwanted reflections.

Light Pollution Reduction
This filter blocks spectral lines from mercury and sodium-vapor lamps while allowing most visible light and H-alpha emissions to pass through. It ensures that important emission lines and the spectral range visible to dark-adapted eyes are preserved.

Optimized Usage
The filter is best suited for aperture ratios between 1:3 and 1:15. Transmission losses and chromatic distortions are minimal unless used with extremely bright aperture ratios, such as 1:2 or more. It works effectively with telescopes of all aperture sizes.

Applications

• Visual Observation: Not recommended for urban skies but effective in dark-sky conditions to reduce light pollution.
• Photography:
  • Film Photography: Excellent color balance.
  • DSLR Photography (Standard): Enhanced contrast but with shifted color balance.
  • DSLR Photography (Astro-Modified): Near-perfect color balance.

Technical Specifications

• Transmission Rates:
  • 92% at 486nm (H-beta)
  • 92% at 496nm (OIII)
  • 92% at 501nm (OIII)
  • 97% at 656nm (H-alpha)
• Wavelength Range: Passes light from 450–540nm and beyond 650nm.
• Build Quality: Aluminium mount with clip-filter frame for Canon EOS cameras. Glass thickness is 1mm.

The Astronomik CLS filter is diffraction-limited, ensuring no reduction in optical performance, and is resistant to humidity, scratches, and aging effects. It comes in a durable, high-quality filter box for long-term storage and protection.