He was an English astronomer who first started the British Civil Services Commission examination for the post of photographic and spectroscopic assistant at the Royal Observatory, Greenwich. He worked at the observatory for the next forty years measuring the sunspots and checking historic records. He found a lack of reports on sunspots from 1645 to 1715. Instead of questioning this, he started researching and found that there are indeed decades-long times when the sun has very few sunspots. Now we call these periods as Maunder minima.