The Arequipa Observatory

Abstract

PROF. PICKERING has conceived and carried to a successful issue many projects that require both mechanical skill and confidence in his resources. In the gradual development of these schemes, we have seen the modest row of volumes, that contained the annals of the Harvard Observatory prior to his directorate, increase to imposing proportions. We know how deftly he holds the strings that control the operations of many departments outside Harvard, and how efficiently he copes with the work that a whole army of astronomers submits to his examination. But assuredly the equipment and maintenance of the observatory at Arec1uipa will be remembered as one of his most successful achievements. We are apt to think of a subsidiary observatory, especially when situated in a position difficult of access, as one temporarily occupied for a definite purpose, and requiring but few instruments, mounted in buildings of slight construction. But the energy of Prof. Pickering has established in South America an observatory that a State. government, having the resources of a public exchequer at its will, might look upon with satisfaction. We reproduce in Fig. I (p. 250) the general appearance of this astronomical station, some 8000 feet above the level of the sea, and a mere glance will show or suggest how varied must be the work of the observatory, in which all the telescopes under the different sheds are kept constantly employed through every clear night. In the illustration the observer's residence is on the extreme right. Starting from that point and taking the several buildings in order as we approach the left, we have first of all a laboratory with developing rooms attached, next a shed containing a 5-inch visual telescope, which leads on to another containing a 20-inch mirror of short focal length, figured by Dr. Common for the observation of the solar eclipse of 1889. We then pass a building containing the principal clocks and a transit instrument, and come to that containing the Bache telescope of eight inches aperture. Next to this is the 13-inch Boyden telescope under a cylindrical drum roof. To the left of this, and before we come to the buildings occupied by the assistants, is a telescope with a Voigtlander portrait lens as an objective in which are taken photographs of four hours' exposure of faint nebulous regions of considerable extent. To this list of instruments must now be added the Bruce photographic telescope, having an objective doublet of 24 inches aperture, and from Prof. Pickering's last report we learn that a transit photometer similar to that in use at Harvard has been erected. Photographs of all the bright stars from the North to the South Pole are now obtained when they cross the meridian on every clear evening, either at Cambridge or Arequipa or both. Fic. 6.—Map showing the origins of 8331 shocks recorded between 1885 and 1892 in Japan. The large dots indicate the positions of active volcanoes. The small dots indicate the origin of different earthquakes which group themselves into fifteen districts, each marked by a large numeral. (Milne.)