This paper describes the wave-front correction and image stabilisation system (CWS) developed for the Sunrise III balloon-borne telescope, and provides information about its performance as measured during the integration into the telescope and during the 2024 science flight. The fast image stabilisation is done by a correlation tracker (CT) and a fast tip-tilt mirror, low order aberrations such as defocus and coma are measured by a six-element Shack-Hartmann wavefront sensor (WFS) and corrected by an active telescope secondary mirror for automated focus and manual coma correction. The CWS is specified to deliver a stabilised image with a precision of 0.005 arcsec (rms). The autofocus adjustment is specified to maintain a focus stability of 0.01 waves in the focal plane of the CWS.
@article{arxiv.2602.07448,
title = {Sunrise III: The Wavefront Correction System},
author = {Thomas Berkefeld and Alexander Bell and Reiner Volkmer and Frank Heidecke and Tobias Preis and Thomas Sonner and Eiji Nakai and Andreas Korpi-Lagg and Achim Gandorfer and Sami K. Solanki and Jose Carlos del Toro Iniesta and Yukio Katsukawa and Pietro Bernasconi and Alex Feller and Tino L. Riethmüller and Alberto Álvarez-Herrero and Masahito Kubo and Valentín Martínez Pillet and H. N. Smitha and David Orozco Suárez and Bianca Grauf and Michael Carpenter},
journal= {arXiv preprint arXiv:2602.07448},
year = {2026}
}
Comments
21 pages, 10 figures, accepted for publication in Solar Physics as an article of the "Sunrise III Topical Collection"