Added to this would be the changing apparent position of Alpha Centauri B during its long eighty - year elliptical orbit with respect to Alpha Centauri A. (The average speed, at 4.5 degrees per Earth year, is comparable in speed to Uranus here. (en.wikipedia.org)
By laboriously measuring the slight shift in a star's apparent position from January to July, astronomers can calculate its distance. (discovermagazine.com)
They were able to detect the slight offset in the object's apparent position when viewed from opposite sides of Earth's orbit around the Sun. (public.nrao.edu)