728 TABLES 825-884.— ASTRONOMY AND ASTROPHYSICS * 



Astronomy, including astrophysics, is a study of the geometry and physics of 

 the heavenly bodies and the material in the intervening space. This experi- 

 mental science requires some very special apparatus — in general, used in con- 

 nection with large telescopes. Table 825 gives a list of the larger telescopes 

 that are now (1949) in active scientific use. Some definitions and standards 

 and other data on astronomy follow. 



* These tables were prepared under the supervision of D. H. Menzel, of Harvard University, and 

 Edith Janssen Tebo, of Harvard College Observatory. 



TABLE 825— THE LARGEST TELESCOPES IN ACTIVE SCIENTIFIC USE 



(1949) t 



Reflectors 

 (60-inch mirrors and larger) 



Hale Telescope, Palomar Mountain, Calif., U. S. A 200-inch 



Hooker Telescope, Mount Wilson, Calif., U. S. A 100-inch 



MacDonald Observatory, Mount Locke, Tex., U. S. A 82-inch 



Radcliffe Observatory, Pretoria, South Africa 76-inch 



David Dunlap Observatory, Richmond Hill, Ontario, Canada 74-inch 



Dominion Astrophysical Observatory, Victoria, B. C, Canada 72-inch 



Perkins Observatory, Delaware, Ohio, U. S. A 69-inch 



Wyeth Reflector, Harvard Observatory, Oak Ridge, Mass., U. S. A 61 -inch 



Southern Station of the Harvard Observatory, Bloemfontein, South Africa 60-inch 



Mount Wilson Observatory, Mount Wilson, Calif., U. S. A 60-inch 



Cordoba Observatory, Bosque Alegre, Argentina 60-inch 



Refractors 

 (30-inch lenses and larger) 



Yerkes Observatory, Williams Bay, Wis., U. S. A 40-inch 



Lick Observatory, Mount Hamilton, Calif., U. S. A 36-inch 



Astrophysical Section, Observatory of Paris, Mundon, France 33-inch 



Allegheny Observatory, Pittsburgh, Pa., U. S. A 30-inch 



University of Paris Observatory, Nice, France 30-inch 



Schmidt-type telescopes 

 (of large aperture) 



48-inch correction plate, 72-inch mirror, Palomar Observatory, .Calif., U. S. A. 



24-inch correction plate, 36-inch mirror (Burrell Telescope), Warner & Swasey Observa- 

 tory, Case Institute of Technology, Cleveland, Ohio, U. S. A. 



24-inch correcting plate, 33-inch mirror (Jewett Telescope) Harvard Observatory, Oak 

 Ridge, Mass., U. S. A. 



t Prepared by J. J. Nassau, Case Institute of Technology. 



TABLE 826.— APPROXIMATE EQUATION OF TIME** 



The equation of time in this table is to be added algebraically to local apparent solar time to 

 obtain local mean solar time. 



Accurate values of the equation of time may be obtained from the American Ephemeris and 

 Nautical Almanac. 



Jan. 1 + 3 Apr. 1 + 4 July 1 + 4 Oct. 1 -10 



11+8 11 4- 1 11+5 11 —13 



21 +11 21—1 21+6 21 -15 



Feb. 1 +14 May 1 — 3 Aug. 1 + 6 Nov. 1 —16 



11 +14 11 - 4 11+5 11 -16 



21 +14 21—4 21+3 21 -14 



Mar. 1 +13 June 1 — 2 Sept. 1 Dec. 1 —11 



11 +10 11_1 11 _ 3 11 _ 7 



21+8 21+1 21—7 21-2 



•" Prepared by G. M. Clemence, U. S. Naval Observatory. 



SMITHSONIAN PHYSICAL TABLES 



