Japanese researchers look at 800-year-old books and trees for signs of extreme solar events
On Feb. 21, 1204, Japanese poet Fujiwara no Teika described in his diary a bizarre phenomenon: the northern Kyoto skies suddenly burning red at night.
by By Tomoko Otake
Full article here:
https://www.jstage.jst.go.jp/article/pjab/102/4/102_pjab.102.011/_article
Solar cycle at PG:
https://www.gutenberg.org/ebooks/search/?query=solar+cycle
