Antlia 1.25 Inch CaK II 3 nm Filter for Solar Photography in Calcium Light

Antlia 1.25" Calcium Filter for Solar Photography

The filter allows solar photography in the calcium line around 393.3 nm. In calcium light, sunspots are imaged similarly to white light, but with more contrast. The flares, solar granulation, flares and even bright prominences in the edge region of the "solar disk" become visible to the photographer.

Never look at the sun only with the K line filter. A lot of invisible but harmful UV radiation enters your eye. The filter is intended exclusively for photography.

We suggest the use of a monochrome astro camera because it does not have a UV/IR block filter, i.e. it can be light sensitive up to the UV range. Also the Bayer filter of the color cameras darkens light noticeably below 400 nm.

Important note: The photographic solar filter film from Baader is necessary for light attenuation. The visual film (16x denser) would darken the image of the sun too much. For refractors without correctors, you can also use a Herschel wedge instead of the film, whereby the often built-in ND3.0 filter may have to be replaced by an ND1.8 filter.