The Antlia Ca-K solar filter is made of heat-resistant, double-polished substrate. The Ca-K 393.3nm solar filter uses the most advanced multi-coating to produce a sharp 3nm narrow bandpass designed to maximise contrast for high-resolution imaging of sunspots, solar surface granulations and other features visible in Ca-K light.
A high blocking/neutral density of OD5 (0.001%) between 200-1200nm wavelengths and OD3 (0.1%) between 1200-1500nm wavelengths provides excellent resolution. However, it must be remembered that the wavelength for Ca-K (393 nm) makes the sun's features almost invisible to the human eye. Therefore, the Antlia Ca-K filter is not recommended for visual observation. It is designed for use with cameras whose spectral sensitivity far exceeds human vision. Never look at the sun with only the Ca-K filter! Although you cannot see it, a lot of harmful UV radiation penetrates your eye. Please note that the Ca-K 3nm 393.3nm filter may only be used in combination with a Herschel wedge/prism! Please familiarise yourself thoroughly with the correct and safe handling of the filter in a Herschel wedge beforehand.
Never look at the sun with just the Ca-K filter, always use it in combination with a Herschel wedge/prism!
