Jitter sensing and reconstruction from temporal series of solar images: Applications to TuMag

¹ Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, 18008 Granada, Spain
² Spanish Space Solar Physics Consortium (S3PC), https://s3pc.es, Spain
³ Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
⁴ Aalto University, Department of Computer Science, Konemiehentie 2, 02150 Espoo, Finland
⁵ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
⁶ Department of Earth and Planetary Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
⁷ Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 1818588, Japan
⁸ Johns Hopkins Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD, USA
⁹ Institut für Sonnenphysik (KIS), Georges-Köhler-Allee 401a, 79110 Freiburg, Germany
¹⁰ Instituto Nacional de Técnica Aeroespacial (INTA), Ctra. de Ajalvir, km. 4, 28850 Torrejón de Ardoz, Spain
¹¹ National Solar Observatory, 3665 Discovery Drive, Boulder, CO 80303, USA
¹² Universitat de Valencia Catedrático José Beltrán 2, 46980 Paterna-Valencia, Spain
¹³ Instituto Universitario “Ignacio da Riva”. Universidad Politécnica de Madrid. (IDR-UPM), Plaza Cardenal Cisneros 3, 28040 Madrid, Spain
¹⁴ Instituto de Astrofísica de Canarias, Vía Láctea s/n, 38205 La Laguna, Spain
¹⁵ Laboratory for Atmospheric and Space Physics (LASP), University of Colorado Boulder, CO, USA
¹⁶ Geophysical and Astronomical Observatory, Faculty of Science and Technology, University of Coimbra, Portugal
¹⁷ Centre for Integrated Data Science, Institute for Space-Earth Environmental Research, Nagoya University, Furocho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
¹⁸ National Institute for Fusion Science, 322-6 Oroshi-cho, Toki City 509-5292, Japan
¹⁹ Grupo de Estudios en Heliofísica de Mendoza, CONICET, Universidad de Mendoza, Boulogne sur Mer 683, 5500 Mendoza, Argentina
²⁰ Institut für Physik, Universität Graz, Universitätsplatz 5, 8010 Graz, Austria
²¹ Advanced Research Center for Space Science and Technology, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan

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Received: 1 December 2025
Accepted: 4 February 2026

Abstract

Context. Images recorded with the Tunable Magnetograph (TuMag) instrument on board the SUNRISE III balloon observatory are affected by temporal contrast fluctuations. These variations are related to high-frequency vibrations (jitter) of the platform that cannot be entirely compensated by the image stabilization unit of the telescope. Jitter smooths out mid- to high-frequency details and degrades the contrast of images that are integrated over hundreds of milliseconds to achieve the signal-to-noise levels required by the instrument. The temporal variations of jitter hamper the reconstruction of the data and limit the accuracy of the instrument.

Aims. We present a technique that allows us to infer and compensate temporal changes of the amplitude and direction of jitter from two images of the same scene, provided they are recorded close enough in time to prevent the scene from evolving significantly.

Methods. We assess the performance of our method through a dynamical magnetohydrodynamical simulation of the solar scene that is degraded with diffraction effects, noise, and jitter. We evaluate the performance of the algorithm as a function of the jitter amplitude and as a function of the time gap between the two images. We finally apply it to a time series recorded by TuMag to sense and restore the temporal evolution of jitter on the images.

Results. Our numerical experiments show that the algorithm is able to sense jitter with an accuracy better than 0.″005 (≲0.1 px) for images recorded less than 10 s apart and assuming a worst-case scenario with a low signal-to-noise ratio of 100 and induced rms jitter amplitudes as large as 0.″15 in the X and Y directions. When increasing the time interval to 30 s, the errors found are still below 0.″01. For the chosen TuMag series we find that the jitter rms amplitudes vary strongly within the range 0.″05–0.″15 (∼1–4 px) and are anticorrelated to the contrast of the recorded images. Correction of jitter improves the contrast of wavefront-reconstructed images by 2.5% in some cases and reduces the rms variation of contrast along the series by half.