The Future of Astronomy by Edward C. Pickering


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Page 1

My object in calling your attention to this matter is the hope that what
I have to say of the organization of astronomy may prove of use to those
interested in other branches of science, and that it may lead to placing
them on the footing they should hold. My arguments apply with almost
equal force to physics, to chemistry, and in fact to almost every branch
of physical or natural science, in which knowledge may be advanced by
observation or experiment.

The practical value of astronomy in the past is easily established.
Without it, international commerce on a large scale would have been
impossible. Without the aid of astronomy, accurate boundaries of large
tracts of land could not have been defined and standard time would have
been impossible. The work of the early astronomers was eminently
practical, and appealed at once to every one. This work has now been
finished. We can compute the positions of the stars for years, almost
for centuries, with all the accuracy needed for navigation, for
determining time or for approximate boundaries of countries. The
investigations now in progress at the greatest observatories have
little, if any, value in dollars and cents. They appeal, however, to the
far higher sense, the desire of the intellectual human being to
determine the laws of nature, the construction of the material universe,
and the properties of the heavenly bodies of which those known to exist
far outnumber those that can be seen.

Three great advances have been made in astronomy. First, the invention
of the telescope, with which we commonly associate the name of Galileo,
from the wonderful results he obtained with it. At that time there was
practically no science in America, and for more than two centuries we
failed to add materially to this invention. Half a century ago the
genius of the members of one family, Alvan Clark and his two sons,
placed America in the front rank not only in the construction, but in
the possession, of the largest and most perfect telescopes ever made. It
is not easy to secure the world's record in any subject. The Clarks
constructed successively, the 18-inch lens for Chicago, the 26-inch for
Washington, the 30-inch for Pulkowa, the 36-inch for Lick and the
40-inch for Yerkes. Each in turn was the largest yet made, and each time
the Clarks were called upon to surpass the world's record, which they
themselves had already established. Have we at length reached the limit
in size? If we include reflectors, no, since we have mirrors of 60
inches aperture at Mt. Wilson and Cambridge, and a still larger one of
100 inches has been undertaken. It is more than doubtful, however,
whether a further increase in size is a great advantage. Much more
depends on other conditions, especially those of climate, the kind of
work to be done and, more than all, the man behind the gun. The case is
not unlike that of a battleship. Would a ship a thousand feet long
always sink one of five hundred feet? It seems as if we had nearly
reached the limit of size of telescopes, and as if we must hope for the
next improvement in some other direction.

The second great advance in astronomy originated in America, and was in
an entirely different direction, the application of photography to the
study of the stars. The first photographic image of a star was obtained
in 1850, by George P. Bond, with the assistance of Mr. J.A. Whipple, at
the Harvard College Observatory. A daguerreotype plate was placed at the
focus of the 15-inch equatorial, at that time one of the two largest
refracting telescopes in the world. An image of [Greek: alpha] Lyr� was
thus obtained, and for this Mr. Bond received a gold medal at the first
international exhibition, that at the Crystal Palace, in London, in
1851. In 1857, Mr. Bond, then Professor Bond, director of the Harvard
Observatory, again took up the matter with collodion wet plates, and in
three masterly papers showed the advantages of photography in many ways.
The lack of sensitiveness of the wet plate was perhaps the only reason
why its use progressed but slowly. Quarter of a century later, with the
introduction of the dry plate and the gelatine film, a new start was
made. These photographic plates were very sensitive, were easily
handled, and indefinitely long exposures could be made with them. As a
result, photography has superseded visual observations, in many
departments of astronomy, and is now carrying them far beyond the limits
that would have been deemed possible a few years ago.

The third great advance in astronomy is in photographing the spectra of
the stars. The first photograph showing the lines in a stellar spectrum
was obtained by Dr. Henry Draper, of New York, in 1872. Sir William
Huggins in 1863 had obtained an image of the spectrum of Sirius, on a
photographic plate, but no lines were visible in it. In 1876 he again
took up the subject, and, by an early publication, preceded Dr. Draper.
When we consider the attention the photography of stellar spectra is
receiving at the present time, in nearly all the great observatories in
the world, it may well be regarded as the third great advance in
astronomy.

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Books | Photos | Paul Mutton | Fri 29th Mar 2024, 12:31