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Life and Works
they appear in fact to exist, lying on the surface of a hollow sphere. The immediate followers of Bradley used these fixed stars as points of reference by which the motions within the solar system could be determined, or, like Lacaille and Lalande, gathered those immense catalogues of their positions which are so indispensable to the science. Michell and Herschel alone, in England, occupied their thoughts with the nature and construction of the heavens—the one in his study, the other through observation.[1] They were concerned with all three of the dimensions of space.
In his memoir of 1784, Herschel says:
"Hitherto the sidereal heavens have, not inadequately for the purpose designed, been represented by the concave surface of a sphere, in the centre of which the eye of an observer might be supposed to be placed.
- ↑ The memoirs on the parallaxes of stars, written by various astronomers from 1750 to 1800, were mainly directed to the improvement of the methods, or to the discovery of the parallax of some particular star. For example, Lacaille's observations of Sirius, at the Cape of Good Hope, had resulted in a parallax of 9″ for that star—a quantity over forty times too large.
