While at the Cape, he discovered what is now known as Kapteyn's Star which the latter had listed as one of a number included in the Cordoba Durchmusterung but missing from the later Cape Photographic Durchmusterung.
22.
To establish a more exact reference system for the Bonner Durchmusterung, in the late 19th century the astronomers and geodesists began to work on a radioastronomical measurements the FK6 accuracy is now better than ?.1 ".
23.
A chart on an isographic projection, exhibiting all the stars contained in the Bonner Durchmusterung, was designed to show the laws according to which the stars down to the 9 10th magnitude are distributed over the northern heavens.
24.
Besides the work of Schwarzschild, in the following decades important observational programmes such as the " Potsdamer Photometrische Durchmusterung " and the outstanding investigations of Walter Grotrian on the solar corona found recognition all over the world.
25.
In 1886 he began a collaboration with Paul Kempf to assemble the " Potsdam Durchmusterung ", which was a stellar catalogue of all stars in the northern hemisphere with a magnitude of 7.5 or brighter.
26.
In 1886, he was promoted to full astronomer and began a collaboration with his friend, German astronomer Gustav M�ller to perform a massive survey of northern stars with magnitudes brighter than 8.5 found in the Bonner Durchmusterung.
27.
Notable astronomers who have worked in the country include John Herschel who published " Results of astronomical observations made during the years 1834, 5, 6, 7, 8, at the Cape of Good Hope " in 1847 and David Gill whose work include the " Cape Photographic Durchmusterung ".
28.
Together with Adalbert Kr�ger and Eduard Sch�nfeld, Argelander was responsible for the star catalogue known as the " Bonner Durchmusterung ", published between 1852 and 1859, which gave the positions and brightness of more than 324, 000 stars, although it did not cover much of the southern half of the sky.
29.
"Relative " coordinates of numerous stars are collected in catalogues like the Bonner Durchmusterung ( Germany 1852-1862, 200.000 rough positions ), the SAO catalogue ( USA 1966, 250.000 astrometric stars ) or the Hipparcos and Tycho catalogue ( 110.000 and 2 million stars by space astrometry ).
