Bessel, << BEHS uhl, >> Friedrich Wilhelm (1784-1846), was a German astronomer and mathematician. He studied a class of mathematical functions now called “Bessel functions,” which are extensively used in physics today. In 1838, Bessel published the first authentic measurement of a star’s annual parallax, an apparent change in the star’s position. Annual parallax is a result of the earth’s motion around the sun.
Bessel was born on July 22, 1784, at Minden. He died on March 17, 1846.
