Poster - Splinter ATNG   (H 2036)

Design and Assembly of a Light Distribution Point for the IAG FTS

C. Fischer, S. Schäfer, A. Reiners
Georg-August-Universität Göttingen

The Institute for Astrophysics and Geophysics at Göttingen University (IAG) operates a solar telescope in the form of a vertical vacuum telescope, including a 50 cm siderostat, installed on the roof of the Faculty of Physics building. The IAG solar telescope utilizes fibers to bring not only the telescope light, but also other calibration sources into the Fourier Transform Spectrograph (FTS), using it for solar observations with high precision, e.g., the recent spectral line atlases for the integrated and spatially resolved Sun. We present a Light Distribution Point (LDP) designed and built for the FTS. The source fiber changes will be automated, in contrast until now manual replugging was necessary to switch fibers. They are permanently installed in the inputs of the LDP, each fiber has an achromatic lens for collimation. All fibers share the same two output fibers connecting to the FTS, with a fiber feed by using off-axis parabolic mirrors. The automatic fiber switching is made possible by using 45° mirrors for each of the input and two outputs, where pneumatic actuators that allow vertical motion, i.e., moving into or out of the light path.