Astronomik - CLS-Filter T Threads

The Astronomik CLS is our inexpensive solution for the visual deep-sky observation, b&w photography and CCD observation. The
Astronomik CLS filter is the right filter to gain the contrast of nearly all objects under light-polluted skies with all sizes of
telescopes. Due to the design of the transmission curve the filter reduces the sky background and gas nebulae planetary nebulae as
well as open clusters, globular clusters and galaxies are seen better. The Astronomik CLS blocks the emission of Hg and Na
streetlights as well as all Skyglow-lines . All major emission lines from deep-sky objects are passed without suppression. As you
can see from the chart below the most important part of the eye's night-sensitive region is passed with maximum transmission. 
 The filter are optimized for the use with focal ratio from 1:4 to 1:15. Loss of transmission and color displacements, that appear
at other filters, emerge with the Astronomik filters only at extreme fast focal ratios of 1:2 and bigger.

Compared to the 'Deep-Sky' filters sold by other manufacturers the Astronomik CLS shows you more stars and more details in the
nebulae. Because of the high quality of the glass you will see stars as the small pinpoints you know from your scope.

The Astronomik CLS can be used with all sizes of instruments. Even the use in front of binoculars is a great improvement. 

    * High transmission of nearly 100% between 450nm and 530nm
    * transmission of ca 96% at H-alpha
    * total blocking of all unwanted light from light-pollution
    * the ideal all around filter for deep-sky observing, even with small scopes
    * completely resistant against high humidity and scratches
    * highest optical quality on the market