373
Longitude from Washington , 23 m 41.20 s E.
Latitude, 42°' 22' 58.8" 1ST.
Director : E. L. Trouvelot.
II. The Astronomical Observatory of Harvard College .
Longitude from Washington , 23 m 41.11 s E.
Latitude, 42° 22' 48.3" N.
Directors : W. C. Bond, 1839.
G. P. Bond, 1859.
J. Winlock, 1866.
Annexed to Harvard College ; projected in 1815; ground acquired in1842; instruments set up in 1844-’48; a central tower and dome, two ,wings, with a small dome on the western wing. Here it was that G. P.Bond discovered in 1848 the seventh satellite of Saturn (Hyperion),and in 1850 the dusky interior ring inside the bright rings of that planet.Among the chronographs, this observatory possesses the original in-strument of W. 0. Bond, mounted in 1850.
Instruments :
(a) Meridian circle: Makers, Troughton & Simms (glasses by Al-van Clark & Sons); diameter of circles, 36 inches; divided to 5';each circle read by 4 microscopes to 0.1"; aperture of objective, 8£inches; for observations of the sun, aperture employed, 8J inches;magnifying power ordinarily employed, 300 to 350 diameters, (a 1 ) Easttransit circle, by Troughton & Simms ; diameter of circles, 48 inches;divided to 5'; each circle read by 4 microscopes to 0.2"; aperture ofobjective, 4| inches.
(b) Meridian transit instruments: One made by Herbst, of Pulkowa;aperture, 2J inches; magnifying power, up to 200 diameters, (b 1 )Large photometer, mounted in the meridian, for comparing images ofstars during transit.
(c) Equatorial instruments : One made by Merz ; aperture of object-ive, 15 inches; magnifying powers of eye-pieces, 100 to 2,000. (o')West equatorial, by Alvan Clark & Sons ; aperture, 5J inches.
(d) Spectroscopes: Three, described in vol. viii of the Annals of theObservatory .
(e) Photometers and other subsidiary apparatus : One Zollner pho-tometer, and several photometers of other kinds.
(/) Chronographs: Two spring governors, by W. Bond & Son ; onesmall barrel chronograph.
(g) Cloclis: One meantime; maker, Bond, 394; one sidereal; makers,Frodsham, 1327; Bond, 312.