In 1826 Samuel Heinrich Swabe of Dessau in Germany started a series of observations on sunspots, recording each group as it traversed the sun’s disk. Twelve years later he published his counts in Astronomische nachtricten. Searching earlier records, an estimate was made of maximum and minimum sunspot activity back to 1610.

Nature volume 395/ 24^th September 1988, p.341: in Statistical visions in time, a history of time series analysis 1662-1938, Judy L.Klein.

Galileo Galilei (1564-1642), applied the art of mathematics to pendulums, the free fall of bodies, projectiles, and acceleration, and recognised that the planets revolved around the Sun. He did not discover the telescope, which had been in use for many centuries, but likely was more a curiosity than a very useful instrument. He refined the telescope, for the first time grinding lenses accurately enough to see the craters on the Moon. Observing the movement of sunspots, he showed the rotation of the Sun on its axis for the first time. He observed the librations (wobble) of the Moon, but believed that the orbits of the planets must be circular (as they would have to be if gravity existed). Galileo was accused of blasphemy for his support of the Copernican heliocentric theory. After trial in 1633, he narrowly escaped execution. The Pope commuted his prison sentence, and he remained confined on his secluded estate at Arcetri near Florence for the remainder of his life.