TOSC: an algorithm for the tomography of spotted transit chords G. Scandariato, V. Nascimbeni, A. F. Lanza, I. Pagano, R. Zanmar Sanchez and G. Leto A&A, 606 (2017) A134 Published online: 25 October 2017 DOI: 10.1051/0004-6361/201730966