LAUSR

Sunspots can be seen with the unaided eye when they are sufficiently large. Due to the known correlation between the occurrence of unaided-eye sunspot observations and the phase of the solar cycle, these observations frequently provide some insight into the level of solar activity in the past. In this context, we have identified a few unaided-eye sunspot observations in late 1769 in East Asia, analyzed their observational conditions, and compared them with contemporary telescopic sunspot observations. The East Asian records indicate that large sunspots were seen with the aid of a temporary coverage of cloud mist on 1769 November 18 and 20. The contemporary sunspot drawings by Christian Horrebow show extremely large sunspot groups near the disk centre for each occasion. These unaided-eye sunspot observations occurred immediately after the maximum of Solar Cycle 2 and provide a snapshot of the enhanced level of solar activity at that time.