Germanastronomer. Independently of R. C. Carrington, he used observations of sunspots to determine the position of the Sun's equator (and hence its axial inclination) and to establish that it has differential rotation. His finding that the average latitude of spots varies over the course of a solar cycle is known as Spörer's law. He was the first to draw attention to the lack of sunspots in the period 1645–1715, which is now known as the Maunder minimum. An earlier period of low solar activity, 1450–1550, is now known as the Spörer minimum, although he did not discover it.
Subjects: Astronomy and Astrophysics.