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 Institute for the Deaf Louis's Central West End, south of the Washington University Medical School. The westernmost building of the complex is also its oldest, dating to 1928. The institute's original 1916 building was torn down around 2000, when the modern portions of the complex were built. The 1928 building, designed by local architect William B. Ittner, was listed on the National Register of Historic Places in 2015 as a reminder of the institute's early history. Central Institute for the Deaf Central Institute for the Deaf (CID) is a school for the deaf that teaches students using listening and spoken language, also known as