Lunt Ca-K Module with B1200 Blocking Filter in Star Diagonal for 2 inch Focuser LUNT LS12CaKMDd2 (0553503) Calcium-K module in star diagonal, for using normal astronomical telescopes up to 100mm aperture and up to 1080mm focal length as Ca-K solar telescopes. Ca-K module in 90° star diagonal for 2" focuser With integrated blocking filter B1200 for telescopes up to 1080mm focal length This Calcium-K module transforms your normal astronomical telescope into a Ca-K solar telescope. It will be very easy: Put the Ca-K module into the 2" focuser of your telescope, and you are ready for solar observing in the light of the Calcium-K wavelength. Internal narrowband filters allow for a <2.4 Angstrom bandwidth. The Ca-K wavelength is at the edge of the visible light spectrum for human eyes, so for many people visual observing is difficult. However, all details could be captured photographically. Therefore the Ca-K Module is optimized primarily for imaging. For telescopes up to 100mm aperture and up to 1080mm focal length. The Ca-K module is in a 90° star diagonal, for 2" focuser on the telescope side and with T2 connection and for 1.25" eyepieces on the eyepiece side.