Assessment of the CRD approximation for the observer’s frame RIII redistribution matrix Simone Riva, Nuno Guerreiro, Gioele Janett, Diego Rossinelli, Pietro Benedusi, Rolf Krause and Luca Belluzzi A&A, 679 (2023) A87 Published online: 28 November 2023 DOI: 10.1051/0004-6361/202346615