Figure 1: Transmission profile of the Lunt CaII K filter (LS18CaKMDs2).
The orange line shows the theoretical solar spectrum from the BASS2000
catalogue and the thin black line is the measured profile from our
spectrograph for comparison.
Figure 2: Layout of the Kanzelhöhe Observatory Ca II K Telescope.
The chosen lenses L1 and L2 are achromats reducing also non-chromatic aberrations.
The effective focal length of the observed system is about 1500 mm which leads to a mean solar
image size of about 13.9 mm in diameter. In front of the Ca filter there are two shortpass filters for
absorbing (SPF1) and reflecting (SPF2) the wavelengths above approx. 480 nm. The whole system is
integrated into the main KSO patrol telescope.
