4:15 PM - 4:30 PM
[MIS17-07] Historical Records on Auroras in Hokkaido
★Invited Papers
Keywords:aurora, Hokkaido, Mogami Tokunai
Historical research into auroras has recently developed as an interdisciplinary field of study, with an increasing accumulation of research results. Due to its geographical location, Hokkaido is expected to have observed low-latitude auroras in the past, but there are few historical materials and limited detailed observational records. The purpose of this presentation is to introduce historical records on auroras in Hokkaido from the 18th to 19th centuries, to provide information on their background and literature.
1. July 28, Meiwa 7 (September 17, 1770)
Over 70 observational records have been confirmed across various regions of Japan regarding the low-latitude aurora that occurred in 1770. According to the study by Iwahashi (2022), the list of documents recording the aurora of 1770 includes references to materials from Hokkaido, specifically "Kyūki Shōrok" by Matsumae Hironaga. Additionally, similar records on aurora of 1770 can also be found in "Matsumae Nenreki Shōkei," also compiled by Hironaga.
Matsumae Hironaga wrote various chronicles and geographical texts, including "Fukuyama Hifu," considered a compilation of Matsumae Clan documents. "Kyūki Shōroku" is a chronicle focused on the significant political events from 1750 to 1774. This document is estimated to have been completed after 1781. "Matsumae Nenreki Shōkei" covers the period from 1189 to 1799 and is presumed to have been established around 1799. Since the period covered by "Kyūki Shōroku" is included from 1738 to 1801 when Hironaga lived, it cannot be denied that the description of aurora might be a record of phenomena he experienced first-hand. However, it is appropriate to view this historical material as a chronicle rather than a diary.
2. May 4, Bunka 3 (June 20, 1806)
In "Tōkai Santan," it is written that between Haboro and Chikubetsu, there was a light in the north resembling the afterglow of the sunset from night until dawn. "Tōkai Santan" is a travel diary by an individual who journeyed from Edo to Matsumae in 1805 and then accompanied an inspection to Sōya in 1806.
Mogami Tokunai, who accompanied the inspection, conducted latitude surveys during the investigations in 1785 and 1786. In his compilation "Ezokoku Fūzoku Ninjō no Sata," he recorded the latitude of Matsumae as 42 degrees. Tokunai responded to inquiries about this phenomenon by stating, "In locations above 42 degrees north latitude, it is possible for sunlight to penetrate the north." Whether this phenomenon is an aurora requires further examination, but if it is, it can be inferred that Tokunai had a very accurate understanding of auroras.
<References> Please refer to the Japanese abstract provided.
1. July 28, Meiwa 7 (September 17, 1770)
Over 70 observational records have been confirmed across various regions of Japan regarding the low-latitude aurora that occurred in 1770. According to the study by Iwahashi (2022), the list of documents recording the aurora of 1770 includes references to materials from Hokkaido, specifically "Kyūki Shōrok" by Matsumae Hironaga. Additionally, similar records on aurora of 1770 can also be found in "Matsumae Nenreki Shōkei," also compiled by Hironaga.
Matsumae Hironaga wrote various chronicles and geographical texts, including "Fukuyama Hifu," considered a compilation of Matsumae Clan documents. "Kyūki Shōroku" is a chronicle focused on the significant political events from 1750 to 1774. This document is estimated to have been completed after 1781. "Matsumae Nenreki Shōkei" covers the period from 1189 to 1799 and is presumed to have been established around 1799. Since the period covered by "Kyūki Shōroku" is included from 1738 to 1801 when Hironaga lived, it cannot be denied that the description of aurora might be a record of phenomena he experienced first-hand. However, it is appropriate to view this historical material as a chronicle rather than a diary.
2. May 4, Bunka 3 (June 20, 1806)
In "Tōkai Santan," it is written that between Haboro and Chikubetsu, there was a light in the north resembling the afterglow of the sunset from night until dawn. "Tōkai Santan" is a travel diary by an individual who journeyed from Edo to Matsumae in 1805 and then accompanied an inspection to Sōya in 1806.
Mogami Tokunai, who accompanied the inspection, conducted latitude surveys during the investigations in 1785 and 1786. In his compilation "Ezokoku Fūzoku Ninjō no Sata," he recorded the latitude of Matsumae as 42 degrees. Tokunai responded to inquiries about this phenomenon by stating, "In locations above 42 degrees north latitude, it is possible for sunlight to penetrate the north." Whether this phenomenon is an aurora requires further examination, but if it is, it can be inferred that Tokunai had a very accurate understanding of auroras.
<References> Please refer to the Japanese abstract provided.