In-flight UV and polarized-VL radiometric calibrations of the solar orbiter/METIS imaging coronagraph

M. Focardi; G. Capobianco; V. Andretta; C. Sasso; M. Romoli; F. Landini; S. Fineschi; M. Pancrazzi; A. Bemporad; G. Nicolini; S. Pucci; M. Uslenghi; G. Naletto; P. Nicolosi; D. Spadaro; L. Teriaca; U. H. Schühle; E. Antonucci

doi:10.1117/12.2055717

24 July 2014 In-flight UV and polarized-VL radiometric calibrations of the solar orbiter/METIS imaging coronagraph

M. Focardi, G. Capobianco, V. Andretta, C. Sasso, M. Romoli, F. Landini, S. Fineschi, M. Pancrazzi, A. Bemporad, G. Nicolini, S. Pucci, M. Uslenghi, G. Naletto, P. Nicolosi, D. Spadaro, L. Teriaca, U. H. Schühle, E. Antonucci

Author Affiliations +

Proceedings Volume 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray; 914409 (2014) https://doi.org/10.1117/12.2055717
Event: SPIE Astronomical Telescopes + Instrumentation, 2014, Montréal, Quebec, Canada

Abstract

METIS is an innovative inverted occulted solar coronagraph capable of obtaining for the first time simultaneous imaging of the full corona in linearly polarized visible-light (580-640 nm) and narrow-band (± 10 nm) ultraviolet H I Ly-α (121.6 nm). It has been selected to fly aboard the Solar Orbiter¹ spacecraft, whose launch is foreseen in July 2017. Thanks to its own capabilities and exploiting the peculiar opportunities offered by the Solar Orbiter planned orbit, METIS will address some of the still open issues in understanding the physical processes in the corona and inner heliosphere. The Solar Orbiter Nominal Mission Phase (NMP) will be characterized by three scientific observing windows per orbit and METIS will perform at least one in-flight calibration per observing window. The two imaging channels of METIS will be calibrated on ground and periodically checked, verified and re-calibrated in-flight. In particular, radiometric calibration images will be needed to determine the absolute brightness of the solar corona. For UV radiometric calibration a set of targets is represented by continuum-emitting early type bright stars (e.g. A and B spectral types) whose photospheres produce a bright far-ultraviolet continuum spectrum stable over long timescales. These stars represent an important reference standard not only for METIS in-flight calibrations but also for other Solar Orbiter instruments and they will be crucial for instruments cross-calibrations as well. For VL radiometric calibration, a set of linearly polarized stars will be used. These targets shall have a minimum degree of linear polarization (DoLP > 5%) and a detectable magnitude, compatible with the instrument integration times constrained by the desired S/N ratio and the characteristics of the spacecraft orbit dynamics.

Citation Download Citation

M. Focardi, G. Capobianco, V. Andretta, C. Sasso, M. Romoli, F. Landini, S. Fineschi, M. Pancrazzi, A. Bemporad, G. Nicolini, S. Pucci, M. Uslenghi, G. Naletto, P. Nicolosi, D. Spadaro, L. Teriaca, U. H. Schühle, and E. Antonucci "In-flight UV and polarized-VL radiometric calibrations of the solar orbiter/METIS imaging coronagraph", Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 914409 (24 July 2014); https://doi.org/10.1117/12.2055717

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available