Baader 1.25", K-line, 395nm filter
(including AstroSolar photo film ND=3.8, format: 200x290mm for pre-filtering sunlight)
The first 'stacked' 1.25" filter for digital cameras and webcams for doing astrophotography using the calcium lines in the solar spectrum. This filter lets through these two lines, at 393nm and 396nm, resulting in a deep blue image. A region of the Sun then becomes visible, in the light of these calcium lines, lying between the photosphere (observable in white light) and the chromosphere (observable in H-alpha light). Flares scattered over the entire surface of the Sun, bright zones around sunspots (and sunspot groups) and the high density network of super granulation can be imaged. Especially suitable for Newtonian telescopes.
