Astronomik CLS 1.25"

Astronomik CLS 1.25" — broadband light-pollution filter

The Astronomik CLS is Astronomik's choice for observing galaxies, nebulae, star clusters and comets from light-polluted sites. It blocks the emission lines of high- and low-pressure sodium and mercury-vapour lamps and all lines of natural airglow, while passing most visible light and the key nebula emissions.

Wide passband, bright stars

Thanks to its wide passband, the CLS lets a lot of light through, so stars are only slightly dimmed. Astronomik rates it as reasonable for visual use under urban skies, and particularly suited to heavy light pollution. Under dark skies, Astronomik considers it rather unsuitable for visual use.

Photography

The CLS can also be used for imaging from light-polluted areas. With CMOS and CCD cameras it needs an additional Astronomik IR-Block filter. For cameras without an IR-cut filter, Astronomik recommends the CLS-CCD version instead, which has IR blocking built in.

Astronomik quality

Astronomik filters use 1 mm finely polished optical glass, free of striae, stress and bubbles, with an extremely scratch-resistant coating that is fully resistant to humidity and ageing. They are diffraction-limited, parfocal with other Astronomik filters, made in Germany and supplied in a long-lasting filter box.

Optical

Physical

Manufacturer documentation

Astronomik CLS 1.25" product page

Compatibility notes

CLS (visual/DSLR), not CLS-CCD (10208125). No integrated IR block: CMOS/CCD and MC-modified cameras need an additional IR-Block filter.

Additional specifications