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 similar to white light, but with more contrast. The flares, solar granulation, flares and even bright prominences at the edge of the "solar disc" become visible to the photographer.

Never look at the Sun through the CaK line filter alone. A lot of invisible but harmful UV radiation will enter your eye. The filter is intended for photography only.

We recommend the use of a monochrome astro camera, as it does not have a UV/IR blocking filter, i.e. it can be light-sensitive up to the UV range. The Bayer filter on colour cameras also darkens light below 400 nm considerably, apart from the fact that three quarters of the pixels are generally not designed for shorter wavelengths due to the matrix.

Important note: The Baader photographic solar filter film is required for light attenuation. The visual film (16x denser) would darken the image of the sun too much. For refractors without correctors, a Herschel wedge (see below) can be used instead of the film, in which case the ND3.0 filter often fitted may have to be replaced by an ND1.8 filter.

Scope of Delivery:

• Filter