Abstract/Summary

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.