The solar corona during the total eclipse on 1806 June 16: graphical evidence of the coronal structure during the Dalton minimum

Visible coronal structure, in particular the spatial evolution of coronal streamers, provides indirect information about solar magnetic activity and the underlying solar dynamo. Their apparent absence of structure observed during the total eclipses throughout the Maunder minimum has been interpreted as evidence of a significant change in the solar magnetic field from that during modern solar cycles. Eclipse observations available from the more recent Dalton minimum may be able to provide further information, with sunspot activity being between the levels seen during recent solar cycles and in the Maunder minimum. Here, we show and examine two graphical records of the total solar eclipse on 1806 June 16, during the Dalton minimum. These records show significant rays and streamers around an inner ring. The ring is estimated to be ≈0.44 Re in width and the streamers in excess of 11.88 Re in length. In combination with records of spicules or prominences, these eclipse records visually contrast the Dalton minimum with the Maunder minimum in terms of their coronal structure and support the existing discussions based on the sunspot observations. These eclipse records are broadly consistent with the solar cycle phase in the modeled open solar flux and the reconstructed slow solar wind at most latitudes

Mapping the Oriental Sky: proceedings of the seventh International Conference on Oriental Astronomy

[Extract] These proceedings, edited by the undersigned four editors, consist of papers which were presented at the Seventh International Conference on Oriental Astronomy (ICOA-7) held at the National Astronomical Observatory of Japan, Mitaka near Tokyo, during September 6-10, 2010, and refereed by members of the scientific organizing committee of the conference. The International Conference on Oriental Astronomy (ICOA) was initially proposed by Professor Emeritus Nha II-Seong (Yonsei University, Korea), in collaboration with Professor Richard Stephenson (Durham University, Britain), and the first meeting was held at Yonsei University, Seoul, on October 6-11, 1993. \ud \ud The primary purpose of the ICOA was to inspire studies on the history of astronomy in Asian countries and to encourage mutual communication and collaboration between researchers in an international context; scholastic activities in this discipline had until then been conducted mainly on a domestic scale. Another aim of the ICOA was to collaborate with Western researchers who studied Asian history of astronomy. Although it is not clear whether the second meeting was clearly born in mind by the organizers at the time of the Seoul meeting, the ICOA has since then been held regularly, usually triennially, during the past 18 years, up to the ICOA-7. It is also noted that each ICOA has published its official proceedings, including that for the ICOA-6 which is now in print as one of the Astrophysics and Space Science Proceedings series at Springer Verlag