OVERLOOKED SUNSPOT OBSERVATIONS BY HEVELIUS IN THE EARLY MAUNDER MINIMUM, 1653-1684

In the book Machina Coelestis (1679), Johannes Hevelius lists his dail y solar observations from 1653 to 1679. He mentions 19 sunspot groups during this interval, of which 14 are unique to Hevelius and five are confirmed by other observers. There are an additional 9 sunspot groups during this interval that were not observed by Hevelius. In five case s he was not observing, but in the other four cases he did observe but failed to comment upon sunspots. The spots he missed or failed to obs erve tend to occur near the end of his career. This suggests Hevelius occasionally missed sunspots but usually was a reliable observer. Thes e observations are important because they provide us the only known da ily listing of solar observations during the early years of the Maunde r Minimum. They are also important because they were overlooked by Wol f, Spoerer, Maunder, Eddy, and others in their study of solar activity in the seventeenth century. They provide us the best record of the su nspot maximum of 1660 when one sunspot lasted at least 86 days as it t raversed the solar disk four times. The same region was active for sev en solar rotations.