Catalogues of the stars were among the first scientific records
started by man, and so long as only the naked eye was used the work
was not difficult, as only approximate positions were attempted,
even by Hipparchus; but long before the eighteenth century dawned
the problem was entirely changed by the invention of the telescope
and by the provision of accurately divided circles; not only could
better positions be recorded, but the number of stars to be catalogued
was enormously increased, and, furthermore, other objects, nebulæ,
presented themselves in considerable numbers.
In 1801 the star catalogues chiefly relied on were those of Lacaille,
containing about three thousand stars scattered over the whole heavens.
Maskelyne, who was then Astronomer Royal, had published in 1790
a catalogue of thirty-six fundamental stars, chiefly for the
purposes of navigation. The first great catalogue of the century
was the _Fundamenta Astronomiae_ of Bessel, produced in 1818. This
contained three thousand two hundred and twenty-two stars. The Bonn
_Durchmüsterung_, with its catalogue of three hundred and twenty-four
thousand one hundred and ninety-eight stars in the northern hemisphere,
and the corresponding atlas published in 1857–63, was the next
memorable achievement in this direction. For it we have to thank Bessel
and Argelander and a perfect system of work.
Another monumental catalogue dealing with the stars in the southern
heavens has been that of the southern stars observed by Gould (1866).
While the century was closing, another catalogue, far more stupendous
than anything which could be conceived possible a few years ago, was
steadily being compiled. This we owe to the far-sightedness and energy
of Admiral Mouchez, a late director of the Paris Observatory. The work
was commenced in 1892.
The whole heavens, north and south alike, have been divided into zones,
and the chief observatories on the earth’s surface are busy night after
night in taking photographs of that part intrusted to them. The whole
heavens are thus being made to write their autobiography, and the total
gain to the astronomy of the future of this most priceless record can
perhaps be scarcely grasped as yet, although the advantage of being
able at any point of future time to see on a photographic plate what
the heavens are telling now is sufficiently obvious.
Catalogues of the stars have, of course, led to other minor catalogues
of various classes of stars, binary, variable, and the like. In the
later years catalogues of stars according to their spectra have
enriched science.
The first extensive catalogue of stellar spectra was published by
Vogel. It dealt with four thousand and fifty-one stars, and appeared in
1883; it has since been followed by the Draper catalogue, based upon
photographs of the spectra, which contains a much larger number. With
regard to nebulæ, Herschel published his third catalogue in 1802. The
last catalogue of this nature is by Dreyer (1888), and contains seven
thousand eight hundred and forty of these objects. In the time of Tycho
they could be counted on the fingers of one hand.