Astrometric observations of Phobos and Deimos during the 1971 opposition of Mars V. Robert, V. Lainey, D. Pascu, J.-E. Arlot, J.-P. De Cuyper, V. Dehant and W. Thuillot A&A, 572 (2014) A104 Published online: 04 December 2014 DOI: 10.1051/0004-6361/201424384