October 23: Gustav Spörer

Friederich Wilhelm Gustav Spörer

October 23, 1822 – July 7, 1895

Gustav Spörer was a German astronomer.

He is noted for his studies of sunspots and sunspot cycles. In this regard he is often mentioned together with Edward Maunder. Spörer was the first to note a prolonged period of low sunspot activity from 1645 to 1715. This period is known as the Maunder Minimum.

Spörer was a contemporary of Richard Christopher Carrington, an English astronomer. Carrington is generally credited with discovering Spörer's law, which governs the variation of sunspot latitudes during the course of a solar cycle. Spörer added to Carrington's observations of sunspot drift and is sometimes credited with the discovery.

The Spörer minimum was a period of low sunspot activity from roughly 1420 to 1570.

The Lunar crater Spörer is named in his honor.