Sunspot observations during the maunder minimum from the correspondence of John Flamsteed

Abstract

We compile and analyze the sunspot observations made by John Flamsteed for the period 1672 – 1703, which corresponds to the second part of the Maunder Minimum. They appear in the correspondence of the famous astronomer. We include in an appendix the original texts of the sunspot records kept by Flamsteed.We compute an estimate of the level of solar activity using these records, and compare the results with the latest reconstructions of solar activity during the Maunder Minimum, obtaining values characteristic of a grand solar minimum. Finally, we discuss a phenomenon observed and described by Stephen Gray in 1705 that has been interpreted as a white-light flare.