2 papers
astro-ph.SR2019
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…
physics.space-ph2018
The Great Space Weather Event during February 1872 Recorded in East Asia
Hisashi Hayakawa, Yusuke Ebihara, David M. Willis +9
The study of historical great geomagnetic storms is crucial for assessing the possible risks to the technological infrastructure of a modern society, caused by extreme space-weathe…