Antlia CaK 3nm filter

CaK 3nm 393.3nm Filter Specifications

The Antlia CaK solar filter are made of heat resistant double-polished substrate. Antlia CaK 393.3nm solar filter uses the most advanced multicoatings to produce a sharp 3nm narrow bandpass, designed to maximize contrast for high-resolution imaging of sun spots, solar surface granulation and other features that are prominent in CaK light.

A high blocking specification of OD5 (0.001%) between 200-1200nm wavelengths and OD3 (0.1%) between 1200-1500nm wavelengths delivers superb resolution for imaging with the Antlia Cak 3nm solar filter.   It should be noted that the bandpass for Cak (393nm) makes solar features almost invisible to human vision because of the eye's low sensitivity and poor resolving ability at the CaK frequency. Hence, the Antlia CaK filter is not recommended for visual observation. It is designed for imaging with cameras that have spectral responses well beyond human vision.

Never look into the sun with the K-Line filter alone, although you don’t perceive it, there is a lot of harmful UV radiation entering your eye.

Please note Cak 3nm 393.3nm filter is screwed in Antlia Herschel Wedge Prism. You do not need to buy it separately if you use our Herschel Wedge Prism.