Stellar population astrophysics (SPA) with the TNG - The Arcturus Lab C. Fanelli, L. Origlia, E. Oliva, A. Mucciarelli, N. Sanna, E. Dalessandro and D. Romano A&A, 645 (2021) A19 Published online: 22 December 2020 DOI: 10.1051/0004-6361/202039397