aat Acta Astrophys. Tau. Acta Astrophysica Taurica 2712-925X Kiselev Nikolai Nikolaevich, Mosсow, settlement Moskovskii, Tat'yanin Park Str., 12, Moscow, Russia. RU 105 Magnetism and Activity of the Sun - 2023 Conference Proceedings Sunspot magnetic fields in solar cycle 24 on measurements at Crimea and Mount Wilson Akhtemov Zubeir Tsap Yurii Malaschuk Valentina Crimean Astrophysical Observatory, Nauchny 298409 Crimean Astrophysical Observatory, Nauchny 298409 Crimean Astrophysical Observatory, Nauchny 298409 22 03 2025 6 1 19 23 12 03 2025 Copyright (c) 2026 Akhtemov Z., Tsap Y., Malaschuk V. 2026 Zubeir Akhtemov, Yurii Tsap, Valentina Malaschuk The metadata for this submission is licensed under a Creative Commons Attribution 4.0 International License. Copyright and publishing rights for texts published in Acta Astrophysica Taurica is retained by the authors, with first publication rights granted to the journal.Texts are free to use with proper attribution and link to the licensing (Creative Commons Attribution 4.0 International).

We present a comparative analysis of 6235 measurements of maximum magnetic fields of the same sunspots obtained at the Crimean Astrophysical Observatory (CrAO) and the Mount Wilson Observatory (MWO) from 2009 to 2019, with the intensity B exceeding 1.5 kGs on CrAO data. It has been established that the average values of the magnetic fields derived at CrAO and MWO are 2053 and 1914 Gs, respectively. The correlation coefficient between the magnetic field measurements at different observatories is 0.63±0.01, and it decreases with increasing B . The difference between the average values of magnetic fields exceeds 500 Gs for sunspots with B ≥ 2.5 kGs. The maximum values of sunspot magnetic fields for the period under consideration according to CrAO and MWO data are 4.6 and 2.7 kGs, respectively. Possible reasons for data discrepancies are discussed.

Sun solar cycle sunspot magnetic field measurements The work was partially supported by the Russian Science Foundation (No. 22-12-0030, Yu.T. Tsap) and the Ministry of Education and Science (research project No. 1021051101548-7-1.3.8, Z.S. Akhtemov). Akhtemov Z.S., Tsap Yu.T., Malaschuk V.M., 2023. Geomagn. Aeronom., vol. 63, no. 8, pp. 1144–1148. Hale G.E., Ellerman F., Nicholson S.B., Joy A.H., 1919. Astrophys. J., vol. 49, pp. 153–178. Livingston W., Harvey J.W., Malanushenko O.V., Webster L., 2006. Solar Phys., vol. 239, pp. 41–68. Lozitska N.I., Lozitsky V.G., Andryeyeva O.A., et al., 2015. Adv. Space Res., vol. 55, pp. 897–907. Pevtsov A. et al., 2019. Astron. Astrophys., vol. 628, id. A103, pp. 1–14. Severnyi A.B., Stepanov V.E., 1956. Izv. Krymsk. Astrofiz. Observ., vol. 16, pp. 3–11. (In Russ.) Stepanov V.E., Petrova N.N., 1958. Izv. Krymsk. Astrofiz. Observ., vol. 18, pp. 66–95. (In Russ.) Tsap Yu.T., Perebeynos V.A., Borisenko A.V., et al., 2019. Astron. Astrophys. Trans., vol. 31, iss. 3, pp. 363–368.