A real gain in polluted environments

The Astronomik CLS is an economical filter for visual observation, black and white photography and CCD photography of nebulae, galaxies and star clusters with astronomical instruments of all sizes.

The Astronomik CLS blocks light from the spectral lines of mercury and sodium vapor lamps and passes most visible light and H-alpha emissions. All important emission lines, as well as the spectral region that the highly dark-adapted eye can see, can pass through the filter.

Main use

The filters are optimized for use with aperture ratios from F/3 to F/15. Transmission losses and chromatic distortions, which are problems with other filters, only appear with Astronomik filters when extremely bright aperture ratios of F/2 and above are used. The CLS filter is suitable for use with telescopes of all aperture sizes.

info:

•     Visual observation (dark sky): good, to reduce light pollution from mercury vapor lamps (public lighting)
•     Visual observation (urban sky): Good, a UHC-E or UHC filter is more suitable
•     Film photography: very good, the color balance is almost perfect
•     CCD photography: good, when used with additional IR block filter
•     DSLR photography (original): good, color balance shifted but contrast improved
•     DSLR photography (astro modified): Very good, the color balance is almost perfect
•     DSLR photography (modified MC): good, when used with additional IR block filter
•     Webcam / video (planets): not suitable
•     Webcam / Video (Deep Sky): Very good, if light pollution is a big problem

Technical data

•     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)
•     go from 450 to 540nm and beyond 650nm
•     Parfocal with other Astronomik filters
•     Glass thickness: 1mm
•     Completely resistant to high humidity, scratches and the effects of aging
•     Diffraction limited, the filter will not reduce the optical performance of your telescope!
•     Astronomik filters come in a high quality, durable filter housing
•     Since 2008 we have been shipping filters with an all new design. Any type of halo or strange reflection is a matter of the past