Cape Photographic Durchmusterung

Kapteyn’s contacts with David Gill led him to accept a carefully orchestrated suggestion by Gill to measure the plates the latter was taking for a Durchmusterung (catalogue of star positions) of the southern skies, using photographic plates for the first time. This work, involving a new method of parallactic measurement, devised by Kapteyn, took more than twelve years and the final result was the publication of 454,875 star positions and magnitudes in the Cape Photographic Durchmusterung, completed in 1900. Kapteyn became also associated with the international Carte du Ciel project to provide star catalogues and maps of the whole sky. He found himself unable to persuade the leaders of the project to accept his method of parallactic measurement. The Carte du Ciel provided serious problems with regard to the funding of Gill’s work on the CPD, owing to obstruction by Astronomer Royal William Christie.