98 citations · 275 across the 11 of their papers we have counts for
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Sunspot Observations by Hisako Koyama: 1945-1996
Hisashi Hayakawa, Frédéric Clette, Toshihiro Horaguchi +4
The sunspot record is the only observational tracer of solar activity that provides a fundamental, multi-century reference. Its homogeneity has been largely maintained with a succe…
Temporal and Spatial Evolutions of a Large Sunspot Group and Great Auroral Storms around the Carrington Event in 1859
Hisashi Hayakawa, Yusuke Ebihara, David M. Willis +10
The Carrington event is considered to be one of the most extreme space weather events in observational history within a series of magnetic storms caused by extreme interplanetary c…
Revisiting Kunitomo's Sunspot Drawings during 1835-1836 in Japan
Masashi Fujiyama, Hisashi Hayakawa, Tomoya Iju +7
We revisit the sunspot drawings made by the Japanese astronomer Kunitomo Toubei during 1835-1836 and recount the sunspot group number for each image. There are two series of drawin…