Multi-purpose grating spectrograph for the 4-meter European Solar Telescope A. Calcines *1 , M. Collados 1 , A. Feller 2 , B. Gelly 3 , B. Grauf 2 , J. Hirzberger 2 , A. López Ariste 3 , R. L. López 1 , P. Mein 4 , F. Sayéde 4 1 Instituto de Astrofísica de Canarias, C/. Vía Láctea s/n, La Laguna, 38205, Tenerife, Spain; 2 Max Planck Institute for Solar System Research, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany; 3 THEMIS, Avenida Menceyes 93, ES-38205, La Laguna, Spain; 4 L’Observatoire de Paris-Meudon, place Jules Janssen 5, 92195, Meudon, France ABSTRACT This communication presents a family of spectrographs designed for the European Solar Telescope. They can operate in four different configurations: a long slit standard spectrograph (LsSS), two devices based on subtractive double pass (TUNIS and MSDP) and one based on an integral field, multi-slit, multi-wavelength configuration. The combination of them composes the multi-purpose grating spectrograph of EST, focused on supporting the different science cases of the solar photosphere and chromosphere in the spectral range from 3900 Å to 23000 Å. The different alternatives are made compatible by using the same base spectrographs and different selectable optical elements corresponding to specific subsystems of each configuration. Keywords: Spectrographs, imaging-spectroscopy, integral field spectroscopy, spectro-polarimetry, solar telescope. 1. INTRODUCTION Spectroscopy is one of the most used techniques in astronomy because it offers broad information about the observed object. For solar physics, this technique, as well as polarimetry, is the main source of information. In addition, both can be combined to get, simultaneously, information about the physical characteristics of solar magnetic structures. Along the years, conventional spectroscopy has been evolving into the current solar spectrographs. In particular, four different concepts 1 are proposed for the 4-meter aperture European Solar Telescope 2 : a long-slit standard spectrograph (LsSS), two devices based on a subtractive double pass, TUNIS and MSDP, and an integral field, multi-slit and multi- wavelength spectrograph. All of them compose the multi-purpose grating spectrograph of EST, which support the different science cases and provide versatility to the telescope. The aim of this family of spectrographs is the study of phenomena taking place in the solar photosphere and chromosphere to analyze in depth the evolution of their associated magnetic structures and understand the solar behavior that can also been extrapolated to other stars. 2. MULTI-PURPOSE GRATING SPECTROGRAPH The four spectrograph proposals for EST are compatible with the use of the same base spectrograph. The covered spectral range goes from the visible (3900Å) to the near-infrared (23000Å) and 8 simultaneous wavelengths can be observed together, five visible and 3 near-infrared. Since, for all stellar atmospheres, a different optical opacity is associated to each spectral line, the multi-wavelength capability allows the simultaneous observation of several layers of the solar atmosphere. Some of the most restrictive science programs in terms of requirements are presented in Calcines et al. 1 *azcr@iac.es; phone +34 922 605 730; fax +34 922 605 210 Ground-based and Airborne Instrumentation for Astronomy IV, edited by Ian S. McLean, Suzanne K. Ramsay, Hideki Takami, Proc. of SPIE Vol. 8446, 84466T · © 2012 SPIE · CCC code: 0277-786X/12/$18 · doi: 10.1117/12.925300 Proc. of SPIE Vol. 8446 84466T-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 04/29/2013 Terms of Use: http://spiedl.org/terms