Sunspots during the Maunder Minimum from Machina Coelestis by Hevelius

摘要

We revisited the sunspot observations published by Johannes Hevelius in hisbook Machina Coelestis (1679) corresponding to the period 1653-1675 (just inthe middle of the Maunder Minimum). We show detailed translations of theoriginal Latin texts describing the sunspot records and provide the generalcontext of these sunspot observations. From this source only, we present anestimate of the annual values of the Group Sunspot Number based only on therecords that explicitly inform about the presence or absence of sunspots.Although we obtain very low values of the Group Sunspot Number, in accordancewith a grand minimum of solar activity, these values are significantly higherin general than the values provided by Hoyt and Schatten (1998) for the sameperiod.