ORIGINAL RESEARCH article
Front. Astron. Space Sci.
Sec. Stellar and Solar Physics
This article is part of the Research TopicWhite-Light Polarimetric Investigation of the Solar Corona and Associated DynamicsView all articles
The COronal Diagnostic EXperiment (CODEX): pre-flight polarimetric characterization
Provisionally accepted
Marta Casti1,2,3*
Jeffrey Newmark3*
Yeon-Han Kim4
Gerardo Capobianco1
Donguk Song4
Sung-Hong Park4
Su-Chan Bong4
Kyung-Suk Cho4Seonghwan Choi4Qian Gong3Ji-Hye Baek4
Jongyeob Park4
Jihun Kim4
Heesu Yang4
Nelson L Reginald2,3
Nicholeen Viall3
Silvano Fineschi1
Federico Landini1Davide Loreggia1Luca Zangrilli1Lucia Abbo1- 1Osservatorio Astrofisico di Torino (INAF), Pino Torinese, Italy
- 2The Catholic University of America, Washington, United States
- 3NASA Goddard Space Flight Center, Greenbelt, United States
- 4Korea Astronomy and Space Science Institute, Daejeon, Republic of Korea
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The COronal Diagnostic EXperiment (CODEX) is an externally occulted solar coronagraph designed to observe the linearly polarized K-corona to simultaneously measure the electron density, kinetic temperature, and speed. The objective of this work is to provide a detailed description of the characterization of the CODEX coronagraph from a polarimetric point of view. The final goal is to minimize the uncertainties associated with the outcome of the observation data analysis by removing the contributions of artifacts introduced by the optical elements within the instrument. This aspect is particularly critical for the CODEX coronagraph, since it is provided with a polarization image sensor, the IMX253MZR manufactured by Sony, that spatially modulates the incoming light beam. Moreover, the optical path of the instrument is composed of several elements including two fold-mirrors positioned at 90 degrees, a system that is notoriously a source of polarization aberrations. The methodology used consists of introducing a light beam with a known polarization state into the instrument and measuring its response. Repeated measurements for different states of polarization of the incoming beam allow one to derive the matrix that connects the Stokes vector of the input light to the intensity measured by the detector. The outcome of this analysis is represented by this matrix, which will be used to derive the Stokes vector of the coronal light from the data acquired by CODEX during its mission and that takes into account the instrumental effects. This will minimize the instrumental effects on coronal polarization that occur if one simply derives the Stokes vector by combining the observed polarized images.
Keywords: solar corona, Solar coronagraph, Calibration, Polarization camera, Polarimetry
Received: 06 Aug 2025; Accepted: 27 Nov 2025.
Copyright: © 2025 Casti, Newmark, Kim, Capobianco, Song, Park, Bong, Cho, Choi, Gong, Baek, Park, Kim, Yang, Reginald, Viall, Fineschi, Landini, Loreggia, Zangrilli and Abbo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Marta Casti
Jeffrey Newmark
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