104
6 Laboratory and Statistical Astronomy
Fig. 6.9 The proper motion of Kapteyn’ star in the sky between 1975 (top), 1990 (middle)
and 1996 (below). This figure is produced by the author from public, digitized Sky
Surveys [61]
been photographed in 1890 and 1893 for the CPD, and the relevant part of
the sky had also been mapped out as part of what was to become the Córdoba
Durchmusterung . But Kapteyn could not find the star in these data. At the
Cape, David Gill’s assistant Robert Thorburn Ayton Innes (1861–1933) had
noticed that in a nearby position a bright star had been seen at Córdoba in
1873; it therefore seemed to be a case of very large proper motion. Observations
by Innes at the Cape Observatory in 1897 confirmed this; the star moved in the
sky at an unprecedented speed of almost 9 arcseconds per year. Fig. 6.9 shows
photographs from more recent years, which clearly illustrate the displacement.
Kapteyn published this discovery also on behalf of the astronomers at the
Cape, mentioning Innes in particular, in the Astronomische Nachrichten. But
not long after that, the British magazine the Observatory accused Kapteyn of
flaunting the feathers of the ‘real’ discoverer of the star, Innes. This brought
6 Laboratory and Statistical Astronomy
Fig. 6.9 The proper motion of Kapteyn’ star in the sky between 1975 (top), 1990 (middle)
and 1996 (below). This figure is produced by the author from public, digitized Sky
Surveys [61]
been photographed in 1890 and 1893 for the CPD, and the relevant part of
the sky had also been mapped out as part of what was to become the Córdoba
Durchmusterung . But Kapteyn could not find the star in these data. At the
Cape, David Gill’s assistant Robert Thorburn Ayton Innes (1861–1933) had
noticed that in a nearby position a bright star had been seen at Córdoba in
1873; it therefore seemed to be a case of very large proper motion. Observations
by Innes at the Cape Observatory in 1897 confirmed this; the star moved in the
sky at an unprecedented speed of almost 9 arcseconds per year. Fig. 6.9 shows
photographs from more recent years, which clearly illustrate the displacement.
Kapteyn published this discovery also on behalf of the astronomers at the
Cape, mentioning Innes in particular, in the Astronomische Nachrichten. But
not long after that, the British magazine the Observatory accused Kapteyn of
flaunting the feathers of the ‘real’ discoverer of the star, Innes. This brought