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astro-ph.SR2026
Analyses on Christoph Clavius' Reports of Total Solar Eclipses in 1560 and 1567: Key References for the Centennial Variations of the Earth's Rotation Speed and the Solar Radius
Hisashi Hayakawa, Mitsuru Sôma, Jean-Pierre Rozelot +4
Variations in solar radius (hereafter R_Sun) is a key reference for solar magnetic activity in time. The sunlight amount may have varied with R_Sun and had an effect on the Earth's…
astro-ph.SR2026
Analyses on Wassenius' Report for Total Solar Eclipse in 1733: Quantifications of the Solar Radius and the Earliest Reported Prominences
Hisashi Hayakawa, Mitsuru Sôma, Noortje Peek +3
Total solar eclipses (TSEs) offer a unique opportunity to observe the solar atmosphere, detect limb phenomena, and accurately measure the solar radius. Following the TSE in 1733, W…
astro-ph.SR2019
Reconstructing solar magnetic fields from historical observations V. Sunspot magnetic field measurements at Mount Wilson Observatory
Alexei A. Pevtsov, Kseniya A. Tlatova, Alexander A. Pevtsov +7
Context. Systematic observations of magnetic field strength and polarity in sunspots began at Mount Wilson Observatory (MWO), USA in early 1917. Except for a few brief interruption…