Zhang Xianyu, Arcidiacono Carmelo, Conrad Albert R, Herbst Thomas M, Gaessler Wolfgang, Bertram Thomas, Ragazzoni Roberto, Schreiber Laura, Diolaiti Emiliano, Kuerster Martin, Bizenberger Peter, Meschke Daniel, Rix Hans-Walter, Rao Changhui, Mohr Lars, Briegel Florian, Kittmann Frank, Berwein Juergen, Trowitzsch Jan
Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg,Germany.
Opt Express. 2012 Mar 26;20(7):8078-92. doi: 10.1364/OE.20.008078.
LINC-NIRVANA is a near-infrared Fizeau interferometric imager that will operate at the Large Binocular Telescope. In preparation for the commissioning of this instrument, we conducted experiments for calibrating the high-layer wavefront sensor of the layer-oriented multi-conjugate adaptive optics system. For calibrating the multi-pyramid wavefront sensor, four light sources were used to simulate guide stars. Using this setup, we developed the push-pull method for calibrating the interaction matrix. The benefits of this method over the traditional push-only method are quantified, and also the effects of varying the number of push-pull frames over which aberrations are averaged is reported. Finally, we discuss a method for measuring mis-conjugation between the deformable mirror and the wavefront sensor, and the proper positioning of the wavefront sensor detector with respect to the four pupil positions.
