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CLS-CCD

Available in 1.25", 2", EOS-C

The Optolong CLS (City Light Suppression) broadband filter is designed to improve the visibility of emission deep sky objects. It selectively reduces the transmission of wavelengths of artificial light, specifically those produced by mercury vapour lamps, both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).

Compared to the UHC filter, the CLS has a wider bandpass so it is preferred in areas with mild to moderate light pollution. It rejects the typical wavelength associated with artificial light and it is highly transparent in the main emission nebula lines: OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm) as well as SII (672nm).

Different from the Optolong CLS filter, the Optolong CLS-CCD cuts off the infrared radiation between 700-1100nm (IR/UV Cut). It works with both astronomy cameras and modified DSLR's for astrophotography. 

Light pollution filters do not eliminate the effects of light pollution or increase the object’s brightness, instead they increase the contrast between objects and the night sky.

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CLS-CCD-spectrum.png

Broad transmission

High transmission of the main nebula emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm) as well as SII (672nm).

Blocks artificial light

Cuts through mercury vapour, high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere.

Multi-coated optics

All Optolong filters feature multi-layer anti-reflection coatings.

Schott optical glass

2mm thick glass made of Schott monolithic optical substrate (non-glued), in ultra-thin, CNC-machined, anodized filter cell (1mm for clip on DSLR series).

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