Popular Science Monthly/Volume 17/June 1880/Sketch of Professor Otto Wilhelm Struve

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PSM V17 D156 Otto Wilhelm Struve.jpg
OTTO WILHELM STRUVE.
 


SKETCH OF PROFESSOR OTTO WILHELM STRUVE.
By Professor SIMON NEWCOMB.

OTTO WILHELM STRUVE, now Director of the Pulkowa Observatory, was born at Dorpat, Russia, May 7, 1819. His father was Dr. Wilhelm Struve, Director of the Dorpat Observatory, and one of the most distinguished of European astronomers. While the son Otto was still a youth, the father imbued the Emperor Nicholas, whose confidence he enjoyed in a high degree, with the notion of erecting the greatest observatory in the world, and thus adding to the luster of his reign and associating his name with the history of science. Thus arose the great Observatory of Pulkowa, some twelve miles south of St. Petersburg, which has sometimes been called the astronomical capital of the world. The work of erecting the observatory, constructing the instruments, and getting the whole established and at work, occupied the years from 1835 to 1840. On the removal of the family to the new establishment, Otto, although only a little over twenty years of age, commenced work as an assistant to his father. His first serious work was an examination of all the stars in the northern heavens, made with the great refractor, in order to detect new double stars. The result was a catalogue of many hundred double stars, all before unknown, and many very close and difficult. The subject of double stars was one which seemed to belong especially to the Struve family, their observations and measurements having been at Dorpat the great work of the father, who thus became preeminent in this branch of research. His "Mensuræ Micrometricæ" is one of the standard astronomical works of the century, a book whose magnificent proportions correspond to the labor expended in its preparation. The next considerable work of the son, and one which has been of enduring value, was a determination of the constant of precession, or, to speak more popularly, of the annual amount of motion of the equinox among the stars. His result has been the accepted standard for thirty years, and the work won the gold medal of the Royal Astronomical Society in 1850.

In 1847 and 1848 he made a series of observations of the satellites of Uranus and Neptune with the great equatorial. His observations of the satellites of Neptune gave the first mass of that planet, which was received with much confidence, but the very unfavorable situation of the planet rendered the result more erroneous than was at first supposed. It has since been proved that the observations made about the same time by Bond, at the Harvard Observatory, gave a result much nearer the truth. While on this work he commenced a search for the inner satellites of Uranus, which had been suspected by Sir William Herschel, but have since been proved not to exist. He succeeded, however, in making several observations of what he at the time supposed to be a new inner satellite, but did not succeed in getting a sufficient number to establish the orbit. The existence of two inner satellites has since been established, and it is probable that Struve's observations were sometimes on one of them and sometimes on the other.

The field covered by Struve's subsequent labors is so large and his papers so numerous that it is not easy to give any untechnical account of his works. He has determined the parallax of several stars, made a careful series of observations on the rings of Saturn, made several journeys to observe solar eclipses, and had general charge of the geodetic operations in the Russian Empire. His greatest recent work has been a continuation of the work of his father on double stars. In 1878 the observations of this class, which he had been making for thirty-five years, were all collected and published in the ninth volume of the "Pulkowa Observations."

In 1862 he succeeded his father as Director of the Pulkowa Observatory. Since that time his energies have been as much occupied with the general direction of the establishment as with independent scientific work. His family has been distinguished by the managing capacity and diplomatic skill of its members, some of whom hold high positions in the civil and diplomatic service of the Government. The subject of our sketch is, in this respect, not inferior to his relatives; and the great efficiency which the observatory has attained under his direction is due as much to his cautious temper, good sense, and judicious management, as to his scientific ability.

The last enterprise undertaken by Struve is of special interest to us. For many years the great telescope at Pulkowa, and its brother instrument at Cambridge, both of fifteen inches aperture, were the largest successful refractors in the world. With the construction of the eighteen-inch telescope for Chicago in 1862, the introduction of larger instruments was inaugurated and continued until the great Washington telescope left that at Pulkowa far behind. This was so far contrary to the ideas of the Pulkowa Observatory that about a year ago the Russian Government authorized Struve to negotiate for the construction of a larger refractor than any yet made. The most difficult and delicate matter was the objective, and, after a visit to the principal European workshops, he determined to come to America for the purpose of conferring with Alvan Clark and Sons, and inspecting their chef-d'oeuvre at Washington. On arriving here in August last he spent several weeks in visiting friends and institutions. At the Saratoga meeting of the American Association for the Advancement of Science, he had an opportunity of making the acquaintance of many of our scientists. The result of his visit to Cambridge was the completion of a contract with the Clarks for a thirty-inch object-glass, which, it is hoped, may be completed within two years if the glass disks can be procured from the makers of optical glass. The mounting of the telescope is to be made by the Repsolds at Hamburg. Having executed his mission, he sailed for his home on September 13, 1879.