Selman, Fernando J.Bian, FuyanBlanchard, IsraelBrillant, StephaneCoccato, LodovicoCristiani, StefanoHibon, PascaleKakkad, DarshanMehner, AndreaMoehler, SabineParraguez, DiegoReyes, ClaudiaRivinius, ThomasVera, SergioVogt, Frédéric P.A.Weilbacher, Peter M.Yang, Bin2026-01-012026-01-010004-6337ORCID:/0000-0001-9632-2706/work/180548365https://hdl.handle.net/1885/733802020We report the serendipitous discovery of a redshift 3.68 quasar while validating the star WD 0308-565 as a spectrophotometric standard star for the Multi-Unit Spectroscopic Explorer (MUSE) calibration plan. Based on the MUSE observations, the luminosity of the quasar at 1350A (L1350) is 4.71 × 1045 erg s−1. The black hole mass is 2.5 × 109 Mʘ, and bolometric luminosity is 1.57 × 1047 erg s−1. Present in the field of view of a star in the calibration plan of the instrument makes this a very valuable quasar as it will receive many repeated visits in the coming years making it an ideal candidate for reverberation mapping studies.6enPublisher Copyright: © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheimquasars: Individual: (J030946.62-562411.2)techniques: Spectroscopy2020-01-0110.1002/asna.20201363785079710348