Impact of the image alignment over frequency for the VLBI Global Observing System Ming H. Xu, Tuomas Savolainen, James M. Anderson, Niko Kareinen, Nataliya Zubko, Susanne Lunz and Harald Schuh A&A, 663 (2022) A83 Published online: 18 July 2022 DOI: 10.1051/0004-6361/202140840