10 citations · 13 across the 2 of their papers we have counts for
2 papers
astro-ph.SR2019★ 3 cited
A Transit of Venus Possibly Misinterpreted as an Unaided-Eye Sunspot Observation in China on 9 December 1874
Hisashi Hayakawa, Mitsuru Sôma, Kiyotaka Tanikawa +6
Large sunspots can be observed with the unaided eye under suitable atmospheric seeing conditions. Such observations are of particular value because the frequency of their appearanc…
astro-ph.SR2019★ 10 cited
The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity
Hisashi Hayakawa, F. Richard Stephenson, Yuta Uchikawa +5
The anomalous concentration of radiocarbon in 774/775 attracted intense discussion on its origin, including the possible extreme solar event(s) exceeding any events in observationa…