Challenges in the determination of the interstellar flow longitude from the pickup ion cutoff A. Taut, L. Berger, E. Möbius, C. Drews, V. Heidrich-Meisner, D. Keilbach, M. A. Lee and R. F. Wimmer-Schweingruber A&A, 611 (2018) A61 Published online: 27 March 2018 DOI: 10.1051/0004-6361/201731796