Friedrich Wilhelm Bessel (German: [ˈbɛsəl]; 22 July 1784 – 17 March 1846) was a German astronomer, mathematician (systematizer of the Bessel functions, which were discovered by Daniel Bernoulli). He was the first astronomer to determine the distance from the sun to another star by the method of parallax.
Although he left school at the age of 14, he was appointed in January 1810 as director of the Königsberg Observatory by King Frederick William III of Prussia. On the recommendation of fellow mathematician and physicist Carl Gauss he was awarded an honorary doctor degree from the University of Göttingen in March 1811.
Bessel won the Gold Medal of the Royal Astronomical Society in 1829 and 1841. The asteroid 1552 Bessel was named in his honour.