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
Catholic (term) then also to the teaching of the church fathers and the councils". The term "Catholic" is commonly associated with the whole of the church led by the Roman Pontiff, the Catholic Church. Other Christian churches that use the description "Catholic" include the Eastern Orthodox Church and other churches that believe in the historic episcopate (bishops), such as the Anglican Communion. Many of those who apply the term "Catholic Church" to all Christians object to the use of the term to designate what they view as only one church within what they understand as the "whole" Catholic Church. In the English