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9 Mount Wilson
Fig. 9.4 The 60 in. telescope at Mount Wilson Observatory. Courtesy the Observatories of the Carnegie Institution for Science Collection, Huntington Library, San Marino,
California [80]
While the 60 in. telescope (Fig. 9.4) was being built, George Hale was looking for research programs for this giant telescope once it would be operational.
He was a solar astronomer himself (today usually called a solar physicist) and
was very impressed by Kapteyn, whom he had met in St. Louis in 1904.
Kapteyn must also have talked to him about his Plan of Selected Areas. The
Plan, as published in 1906, does not contain a commitment from Hale to
participate. Nevertheless, Hale soon appears to have decided that Kapteyn’s
Plan was an ideal program for his 60 in. telescope.
9.1 Hale and Kapteyn
On January 9, 1907, George Hale (Fig. 9.5) wrote to Kapteyn. ‘I am afraid
that you have come to the conclusion that I am not interested in your Plan
of Selected Areas. I do, however, have a great faith in that plan and consider it
of the utmost importance.’ And he asked Kapteyn to what extent the 60 in.
could be useful for it. The construction of the telescope had been considerably