6.3 Parallaxes and Proper Motions
105
out a less pleasant aspect of Kapteyn’s character; he was much offended by this
and wrote a strong letter to David Gill. Eventually Gill published a detailed
explanation of how this had developed, and pointed out that Kapteyn had
indeed carefully mentioned Innes. However, the editors of the magazine stuck
to their opinion. Nevertheless, the star was named after Kapteyn, because he
published its discovery (albeit on behalf of others).
David Gill raised another matter in his correspondence with Kapteyn about
this case. In a discussion of the CPD Karl Hermann Gustav Müller (1851–
1925), the director of the Astrophysikalisches Observatorium in Potsdam,
wrongly claimed that the CPD—and even the idea for it—had sprung from
Kapteyn’s brain. Gill had not made a point of this at the time, nor had he
protested to Müller. But he now suggested that Kapteyn could have objected
publicly or by letter to Müller and set the record straight. Kapteyn admitted
this and wrote extensively about Gill’s participation in the project (but without
mentioning Gill by name) in the Preface to the last part of the CPD. The
correspondence concerning this episode shows that Gill was the most tactful
and the wisest of the two.
However, they remained excellent friends. Gill visited Kapteyn several times
in Groningen, for the first time just before the great Carte du Ciel congress in
Paris in 1887. In her biography [1] his daughter wrote about this first visit:
Mother looked at them with joy, as she was standing in front of the house when
they left arm in arm for the Laboratory (the two small rooms had this grandiose
name in the Kapteyn family). Gill talking loudly and gesticulating, stared at by
the Groningen citizens, Kapteyn, short and modest, quietly happy next to him.
This first visit was a great success, and also the children were delighted with this
big playmate, who had won their hearts notwithstanding his incomprehensible
language. From then on he was ‘Oom Gill’ [Uncle Gill] and remained that
forever.
Kapteyn visited Gill only once in South Africa, but did visit him and his wife
more often when they had moved to London after his early retirement. The
friendship with Anders Donner was just as close; Donner hated writing and
travelling, so contacts were limited to an absolute minimum. Anders Donner
has visited Groningen a couple of times, but as far as I know Kapteyn has never
been to Helsinki.
About Kapteyn’s star the following should be noted. It later turned out to be
one of the closest stars. It is at 12.8 light years from Earth; only 24 other stars
(or star systems) are closer than that. It is a halo star with a very low chemical
abundance (about ten times less than the Sun) and is at least 10 billion years
old. It describes an orbit in space in which it crosses the disk of our Galaxy in
105
out a less pleasant aspect of Kapteyn’s character; he was much offended by this
and wrote a strong letter to David Gill. Eventually Gill published a detailed
explanation of how this had developed, and pointed out that Kapteyn had
indeed carefully mentioned Innes. However, the editors of the magazine stuck
to their opinion. Nevertheless, the star was named after Kapteyn, because he
published its discovery (albeit on behalf of others).
David Gill raised another matter in his correspondence with Kapteyn about
this case. In a discussion of the CPD Karl Hermann Gustav Müller (1851–
1925), the director of the Astrophysikalisches Observatorium in Potsdam,
wrongly claimed that the CPD—and even the idea for it—had sprung from
Kapteyn’s brain. Gill had not made a point of this at the time, nor had he
protested to Müller. But he now suggested that Kapteyn could have objected
publicly or by letter to Müller and set the record straight. Kapteyn admitted
this and wrote extensively about Gill’s participation in the project (but without
mentioning Gill by name) in the Preface to the last part of the CPD. The
correspondence concerning this episode shows that Gill was the most tactful
and the wisest of the two.
However, they remained excellent friends. Gill visited Kapteyn several times
in Groningen, for the first time just before the great Carte du Ciel congress in
Paris in 1887. In her biography [1] his daughter wrote about this first visit:
Mother looked at them with joy, as she was standing in front of the house when
they left arm in arm for the Laboratory (the two small rooms had this grandiose
name in the Kapteyn family). Gill talking loudly and gesticulating, stared at by
the Groningen citizens, Kapteyn, short and modest, quietly happy next to him.
This first visit was a great success, and also the children were delighted with this
big playmate, who had won their hearts notwithstanding his incomprehensible
language. From then on he was ‘Oom Gill’ [Uncle Gill] and remained that
forever.
Kapteyn visited Gill only once in South Africa, but did visit him and his wife
more often when they had moved to London after his early retirement. The
friendship with Anders Donner was just as close; Donner hated writing and
travelling, so contacts were limited to an absolute minimum. Anders Donner
has visited Groningen a couple of times, but as far as I know Kapteyn has never
been to Helsinki.
About Kapteyn’s star the following should be noted. It later turned out to be
one of the closest stars. It is at 12.8 light years from Earth; only 24 other stars
(or star systems) are closer than that. It is a halo star with a very low chemical
abundance (about ten times less than the Sun) and is at least 10 billion years
old. It describes an orbit in space in which it crosses the disk of our Galaxy in