Chroma Clear Filter, 65x65 mm unmounted

Chroma Clear Filter, 65x65 mm unmounted

This filter does not block any light, which makes focusing and luminance shots with purely reflective systems easier. The clear glass filter also protects the camera sensor from dust. The most important application areas of the filters are:

Deep-sky photography with reflector telescopes without corrector

Normally an IR cut filter is needed for astrophotography because lenses or correctors are not corrected for the infrared light. The sharpness would be greatly reduced. The CCD chips are sensitive well into the infrared. With purely reflecting telescopes without a corrector, the complete IR light can be used, you gain more light and have significantly more information on the chip at comparable exposure times.

Luminance images taken with monochrome astro cameras with reflector telescopes without corrector

It makes sense to use a filter with the same thickness for the luminance recording as for the color channels. This saves refocusing.Chroma filters have practically always the same thickness.

Focusing with narrow band line filters

Setting the correct sharpness with dark filters is a problem. The Chroma clear glass filter replaces the Chroma narrow band filter for precise focusing. Afterwards, you simply replace the clear glass filter with the narrow band filter and can start immediately due to the same thickness of the filter substrate.

Alternative: The luminance filter is usually better suited for use on optical systems that contain refractive elements.