Friedrich Bessel

Friedrich Bessel was a 19th-century German mathematician and astronomer renowned for his precise measurements of star positions. His most notable achievement was determining the distance to the star 61 Cygni using parallax—the tiny shift in a star’s position caused by Earth's orbit around the Sun. This breakthrough helped establish a fundamental method for measuring distances in space. Bessel's work laid the groundwork for modern astrometry, the science of accurately charting stars and understanding our universe's scale.