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Proceedings Paper • Open Access

Metis/Solar Orbiter polarimetric visible light channel calibration
Author(s): M. Casti; S. Fineschi; G. Capobianco; M. Romoli; E. Antonucci; G. Nicolini; G. Naletto; P. Nicolosi; D. Spadaro; V. Andretta; M. Castronuovo; G. Massone; R. Susino; V. Da Deppo; F. Frassetto; F. Landini; M. Pancrazzi; L. Teriaca; M. Uslenghi

Paper Abstract

Metis is the solar coronagraph of the ESA mission Solar Orbiter. For the first time, Metis will acquire simultaneous images of the solar corona in linearly polarized, broadband visible light (580-640 nm) and in the narrow-band HI Ly-α line (121.6 nm). The visible light path includes a polarimeter, designed to observe and analyse the K-corona linearly polarized by Thomson scattering. The polarimeter comprises a liquid crystal Polarization Modulation Package (PMP) together with a quarter-wave retarder and a linear polarizer. The Metis PMP consists of two Anti-Parallel Nematic Liquid Crystal Variable Retarders (LCVRs) with their fast axis parallel with respect to each other and a pre-tilted angle of the molecules in opposite direction. This configuration results in an instrumental wide field of view (±7°). The LCVRs provide an electro-optical modulation of the input polarized light by applying an electric field to the liquid crystal molecules inside the cells. A given optical retardance can be induced in the LCVRs by selecting a suitable voltage value. This paper reports the polarimetric characterization of the Visible-light channel for the Metis/Solar Orbiter coronagraph. The retardance-to-voltage calibration of the electro-optical polarimeter was characterized over the entire field of view of the coronagraph yielding a complete “polarimetric flat-field” of the Metis Visible-light channel.

Paper Details

Date Published: 12 July 2019
PDF: 15 pages
Proc. SPIE 11180, International Conference on Space Optics — ICSO 2018, 111803C (12 July 2019); doi: 10.1117/12.2536039
Show Author Affiliations
M. Casti, INAF – Osservatorio Astrofisico di Torino (Italy)
S. Fineschi, INAF – Osservatorio Astrofisico di Torino (Italy)
G. Capobianco, INAF – Osservatorio Astrofisico di Torino (Italy)
M. Romoli, Univ. degli Studi di Firenze (Italy)
E. Antonucci, INAF – Osservatorio Astrofisico di Torino (Italy)
G. Nicolini, INAF – Osservatorio Astrofisico di Torino (Italy)
G. Naletto, Univ. degli Studi di Padova (Italy)
P. Nicolosi, Univ. degli Studi di Padova (Italy)
D. Spadaro, INAF – Osservatorio Astrofisico di Torino (Italy)
V. Andretta, INAF – Osservatorio Astrofisico di Torino (Italy)
M. Castronuovo, Agenzia Spaziale Italiana (Italy)
G. Massone, INAF – Osservatorio Astrofisico di Torino (Italy)
R. Susino, INAF – Osservatorio Astrofisico di Torino (Italy)
V. Da Deppo, CNR-Istituto di Fotonica e Nanotecnologie (Italy)
F. Frassetto, CNR-Istituto di Fotonica e Nanotecnologie (Italy)
F. Landini, INAF – Osservatorio Astrofisico di Torino (Italy)
M. Pancrazzi, Univ. degli Studi di Firenze (Italy)
L. Teriaca, Max Planck Institute for Solar System Research (Germany)
M. Uslenghi, INAF – Osservatorio Astrofisico di Torino (Italy)


Published in SPIE Proceedings Vol. 11180:
International Conference on Space Optics — ICSO 2018
Zoran Sodnik; Nikos Karafolas; Bruno Cugny, Editor(s)

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