%ACaffau, E. [GEPI, Observatoire de Paris, PSL Research University, CNRS, Place Jules Janssen, Meudon, France]%ACaffau, E. [GEPI, Observatoire de Paris, PSL Research University, CNRS, Place Jules Janssen, Meudon, France]%ABonifacio, P. [GEPI, Observatoire de Paris, PSL Research University, CNRS, Place Jules Janssen, Meudon, France]%ABonifacio, P. [GEPI, Observatoire de Paris, PSL Research University, CNRS, Place Jules Janssen, Meudon, France]%AStarkenburg, E. [Leibniz‐Institut für Astrophysik Potsdam (AIP), Potsdam, Germany]%AStarkenburg, E. [Leibniz-Institut für Astrophysik Potsdam (AIP), Potsdam, Germany]%AMartin, N. [CNRS, Observatoire Astronomique de Strasbourg, Université de Strasbourg, UMR, Strasbourg, France, Max‐Planck‐Institut für Astronomie, Heidelberg, Germany]%AMartin, N. [CNRS, Observatoire Astronomique de Strasbourg, Université de Strasbourg, UMR, Strasbourg, France; Max-Planck-Institut für Astronomie, Heidelberg, Germany]%AYouakim, K. [Leibniz‐Institut für Astrophysik Potsdam (AIP), Potsdam, Germany]%AYouakim, K. [Leibniz-Institut für Astrophysik Potsdam (AIP), Potsdam, Germany]%AHenden, A. [AAVSO, Cambridge, MA]%AHenden, A. [AAVSO, Cambridge, MA]%AGonzález Hernández, J. [Instituto de Astrofísica de Canarias, Vía Láctea S/N, 38205 La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Tenerife, Spain]%AGonzález Hernández, J. [Instituto de Astrofísica de Canarias, Vía Láctea S/N, 38205 La Laguna, Tenerife, Spain, Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Tenerife, Spain]%AAguado, D. [Instituto de Astrofísica de Canarias, Vía Láctea S/N, 38205 La Laguna, Tenerife, Spain, Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Tenerife, Spain]%AAguado, D. [Instituto de Astrofísica de Canarias, Vía Láctea S/N, 38205 La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Tenerife, Spain]%APrieto, C. [Instituto de Astrofísica de Canarias, Vía Láctea S/N, 38205 La Laguna, Tenerife, Spain, Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Tenerife, Spain]%APrieto, C. [Instituto de Astrofísica de Canarias, Vía Láctea S/N, 38205 La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Tenerife, Spain]%AVenn, K. [Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada]%AVenn, K. [Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada]%AJablonka, P. [GEPI, Observatoire de Paris, PSL Research University, CNRS, Place Jules Janssen, Meudon, France, Laboratoire d'Astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, Versoix, Switzerland]%AJablonka, P. [GEPI, Observatoire de Paris, PSL Research University, CNRS, Place Jules Janssen, Meudon, France; Laboratoire d'Astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, Versoix, Switzerland]%BJournal Name: Astronomische Nachrichten; Journal Volume: 338; Journal Issue: 6; Related Information: CHORUS Timestamp: 2023-09-02 17:12:10 %D2017%IWiley Blackwell (John Wiley & Sons) %JJournal Name: Astronomische Nachrichten; Journal Volume: 338; Journal Issue: 6; Related Information: CHORUS Timestamp: 2023-09-02 17:12:10 %K %MOSTI ID: 10027349 %PMedium: X %TThe Pristine survey II: A sample of bright stars observed with FEROS %X

Extremely metal‐poor (EMP) stars are old objects formed in the first Gyr of the Universe. They are rare and, to select them the most successful strategy has been to build on large and low‐resolution spectroscopic surveys. The combination of narrow‐ and broad‐band photometry provides a powerful and cheaper alternative to select metal‐poor stars. The ongoing Pristine Survey is adopting this strategy, conducting photometry with the Canada France Hawaii Telescope MegaCam wide‐field imager and a narrow‐band filter centered at 395.2 nm on the Ca II‐H and ‐K lines. In this paper, we present the results of the spectroscopic follow‐up conducted on a sample of 26 stars at the bright end of the magnitude range of the Survey (g⩽15), using FEROS at the MPG/ESO 2.2‐m telescope (manufactured by Zeiss, Oberkochen, Germany). From our chemical investigation on the sample, we conclude that this magnitude range is too bright to use the Sloan Digital Sky Survey (SDSS)gribands, which are typically saturated. Instead, the Pristine photometry can be usefully combined with the AAVSO Photometric All Sky Survey (APASS)griphotometry to provide reliable metallicity estimates.

%0Journal Article