The discovery of sunspots

Although naked-eye observations of sunspots have been recorded sporadically since the first Chinese observations several centuries before the birth of Christ, the year 1611, when sunspots were observed for the first time through the telescope, marks the beginning of the science of astrophysics. Four men share the honour of this discovery: Johann Goldsmid in Holland (1587-1616), Galileo Galilei in Italy (1564-1642), Christopher Scheiner in Germany (1575-1650), and Thomas Harriot in England (1560-1621). It is uncertain which of this international quartet made the first observations, but priority of publication belongs to Goldsmid, or Fabricius, as he is known by his Latinized name. Although his equipment was probably inferior to that of Galileo or of Scheiner, Fabricius made observations of sunspots and used them to infer that the Sun must rotate but did not carry this work beyond these initial observations.

When Scheiner, a Jesuit priest teaching mathematics at the University of Ingolstadt, first observed the spots, he suspected some defect in his telescope. He soon became convinced of their actual existence but failed to persuade his ecclesiastical superiors, who refused to allow him to publish his discovery. This indignity was later shared by the French astronomer, Messier, who in 1780 was similarly prevented from announcing his observation of the return of Halley's comet in that year. Regrettably, such instances of scientific censorship are not uncommon and, in Scheiner's case, played a major role in the controversy that led to the denouncement of Galileo to the Italian inquisition.