Abstract
THE U.S. NAVAL OBSERVATORY, WASHINGTON.—Under the title “Instruments and Publications of the United States Naval Observatory,” the superintendent has circulated a series of photographs of the instruments at present in use in that noble astronomical institution. They are taken by the heliotype process, and comprise (1) the mural circle, mounted in 1844, aperture 4.1 inch; the transit instrument, 5.33 inch aperture, mounted in the same year, and placed in the same room beside the mural circle; the smaller equatorial, mounted in 1844, with which so much good work has been performed, aperture 9.62 inch; the transit-circle, by Pistor and Martins, Berlin, which was mounted in 1860, the aperture of the object-glass 8.52 inch, and the focal length 12 feet 1 inch; a general view of the grand 26-inch refractor, of 32 feet 5.8 inch focal length, mounted in 1873, and one of the most powerful telescopes in the world; the clock-work, &c., of this magnificent instrument is shown on a separate plate. Brief descriptions accompany these heliotypes, and in addition are drawings made with the 26-inch equatorial of the nebula in Orion, the omega nebula, the annular nebula in Lyra, and the planet Saturn. Some account of the foundation of the observatory and a list of its publications from 1845–76 precede the brief description of the instruments of which views are presented.
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Our Astronomical Column . Nature 15, 549–550 (1877). https://doi.org/10.1038/015549d0
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DOI: https://doi.org/10.1038/015549d0