What scientist explained the parallax problem?

The parallax problem, particularly in relation to measuring astronomical distances, was notably addressed by the astronomer Friedrich Bessel in the early 19th century. He successfully calculated the parallax of the star 61 Cygni, providing the first reliable measurement of a star's distance from Earth. Bessel's work demonstrated the effectiveness of using parallax as a method for determining distances to celestial objects, laying the groundwork for modern astrophysics and distance measurement techniques.