Geocentric model explanation in terms of the Earth's revolution about the sun. In 1838, astronomer Friedrich Wilhelm Bessel measured the parallax of the star 61 Cygni successfully, and disproved Ptolemy's claim that parallax motion did not exist. This finally confirmed the assumptions made by Copernicus, providing accurate, dependable scientific observations, and conclusively displaying how distant stars are from Earth. A geocentric frame is useful for many everyday activities and most laboratory experiments, but is a less appropriate choice for solar system mechanics and space travel. While a heliocentric frame is most useful in those cases, galactic and extragalactic astronomy is easier if
Central Illinois Regional Airport for the Central Illinois Air Derby. Billed at the time as the greatest such event in Illinois outside of Chicago, the show included four U.S. Army "ships" from Chanute Field in Rantoul, civilian aviators from places like Aurora, Champaign, Joliet and Kankakee, aerial "stunting" contests and races, parachutists and an air parade over downtown Bloomington. Despite the efforts of local aviation enthusiasts and the business community, attempts to establish long-term passenger service at the Normal field ended in failure. In the fall of 1931, Century Air Lines added Bloomington to its Chicago-to-St. Louis route, and the little grassy square (recently