フリードリヒ・ヴィルヘルム・ベッセル
Friedrich Bessel successfully uses the method of stellar parallax, the effect of Earth's annual movement around the Sun, to calculate the distance to 61 Cygni, the first star other than the Sun to have its distance from Earth measured. Bessel's is a truly accurate measurement of stellar positions, and the parallax technique establishes a framework for measuring the scale of the universe.