Nature June 6th 1872
Transit of Venus
In a letter from General Otto Struve, director of the
Palkowa Observatory and Astronomer Royal of Russia, to Prof. Newcomb, of the
Washington Observatory, detailing the Russian preparations for observing the forthcoming Transit of
Venus, and printed in HARPERS’S WEEKLY, he remarks that the inquiries into the
meteorological conditions of the stations selected have given on the whole,
very satisfactory results, particularly for the station on the coast of the
Pacific Ocean and in Eastern Siberia (84
pr cent of clear sky for December).
In two only of the stations chosen, Tashkent and Astrabad,
these conditions are not sufficiently satisfactory. For this reason the
observers designed for Tashkent will probably go to a place about 100 miles west of that town; and instead of
Astrbad it is proposed to take either the island of Aschuradeh , in the Caspian
Sea, or, of possible to cross the Elburz Mountains and establish observers at
Schahrech, In Persia 9with nearly absolute certainty of clear sky).
The total number of Russian stations will be twenty-four
each of them provided with only one instrument for the transit observation.
These instruments are – three 4 inch heliometers, three photo heliographs, four
6inch equatorial and four 4 inch equatorials, provided with filar micrometres
and spectroscopic apparatus and ten 4 inch telescopes, designed merely for
contact observations. Each station will
also be furnished with clocks, chronometers, and the instruments necessary for
exact determination of time. The principal instruments have already been
ordered.
Most of them will be ready for use in the curse of the
present or beginning of next year. For these instruments the observers are also
in a great part selected. They will all visit Palkowa for a certain time in
1873 to exercise themselves in the observations.
The geographic positions of the stations will be determined
by the transit observers; but all stations on which the transit has been
successfully observed will be carefully determined afterwards by special
expeditions of the general staff or the navy. For this purpose, a principal
line of telegraphic longitudes, will probably be laid next year through all
Siberia to Nicolajevsk, with which line the other stations of that part of
Russia can easily be joined, either by telegraphic or chronometric operations.
With regards to photographic observations, Prof Struve
states that the two observers, one at Vilna and Dr Vogel at Bothkamp, in
Holstein, have been perfectly successful in taking instantaneous observations
with dry plates.
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