Iwahashi Zenbei’s Sunspot Drawings in 1793 in Japan

Abstract

Three Japanese sunspot drawings associated with Iwahashi Zenbei (1756-1811) are shown here from contemporary manuscripts and woodprint documents with the relevant texts. We revealed the observational date of one of the drawings to be 26 August 1793, and the overall observations lasted for over a year. Moreover, we identified the observational site for the dated drawing at Fushimi in Japan. We then compared his observations with group sunspot number and raw group count from Sunspot Index and Long-term Solar Observations (SILSO) to reveal its data context, and concluded that these drawings filled the gaps in understanding due to the fragmental sunspots observations around 1793. These drawings are important as a clue to evaluate astronomical knowledge of contemporary Japan in the late 19 th century and are valuable as a non-European observation, considering that most sunspot observations up to mid-19 th century are from Europe.

Sunspot Observations Made by Hallaschka During the Dalton Minimum

“…Therefore, the incorporation to the database of group counts of new information about sunspot records not previously published is important to improve the temporary coverage of this period. Thus, the recovery of a sunspot drawing made by Iwahashi Zenbei (Hayakawa et al, 2018) on 26 August 1793 and an undated one, during the decline phase of the Solar Cycle 4, and a set of 25 drawings by Jonathan Fisher (Denig and McVaugh, 2017) We found sunspot observations performed by Cassian Hallaschka in 1814 and 1816 (shortly before the maximum of the Solar Cycle 6) which have not yet been included in sunspot studies. The aim of this work is to present these solar observations and to contribute to improve the reconstruction of solar activity of the past, in particular, of the Dalton minimum.…”

Records of sunspots and aurora candidates in the Chinese official histories of the Yuán and Míng dynasties during 1261–1644

“…The most intense geomagnetic storm in history of ground-based telescopic observations is believed to be so-called the "Carrington event" in 1859 (Carrington 1859;Kimball 1960;Tsurutani et al 2003;Cliver & Svalgaard 2004;Hayakawa et al 2016b), with an estimated disturbance storm time (Dst) index of ~ −1760 nT (Tsurutani et al 2003). In this event, a white light flare within a great sunspot on 1859.09.01 observed by Carrington (1859;1863) caused a series of severe magnetic storms and low-latitude auroras up to 23° in magnetic latitude such as Hawaii, Caribbean Islands, or Southern Japan were observed (Kimball 1960;Cliver & Svalgaard 2004;Hayakawa et al 2016b). Recent studies warn us that the same-scaled solar storms can cause severe disasters as serious as 2 trillion USD in case they hit the modern civilization (National Research Council 2008), so that extreme events like Carrington event require intensive studies.…”

New sunspots and aurorae in the historical Chinese text corpus? Comments on uncritical digital search applications

“… We review some applications of the method of electronic searching for historical observations of sunspots and aurorae in the Chinese text corpus by Hayakawa et al (, , , ), Kawamura et al (), and Tamazawa et al (). However, we show strong shortcomings in the digital search technique as applied by them: almost all likely true sunspot and aurora records were presented earlier (e.g., Xu et al ), which are not mentioned in those papers; the remaining records are dubious and often refer to other phenomena, neither spots nor aurorae (this also applies to Hayakawa et al ). The alleged aurorae in Hayakawa et al () and Kawamura et al () show a broad peak around full moon, not expected for aurorae.…”