2nd generation etalons for CARMENES - towards 10 cm/s precision
H.L. Pleteit, S. Schäfer, M. Debus, A. Reiners
Georg-August-Universität Göttingen, Institute for Astrophysics and Geophysics
We present the design of the second generation Fabry-Pérot etalons (FP) for the CARMENES high resolution spectrographs. The update centers around improving temperature stabilization and monitoring. In a proof-of-concept study in our lab a structurally identical FP unit when compared against an iodine cell shows an RMS of 10.6 cm/s over 70 hours of measurement. Additionally, we demonstrate by forward modelling the FP how the quality of the spectral peaks can be improved through alignment and use of larger collimators. We further investigate the throughput and finesse of the new etalons.