414 



TABLE 540. 

 MISCELLANEOUS ASTRONOMICAL DATA- 





Tropical (ordinary) year 

 Sidereal year 

 Anomalistic year 

 Eclipse year 



Synodical (ordinary) month 

 Sidereal month 



= {365.24219879 0.0000000614 (/ i9oo)}days 

 = {365.25636042 + 0.0000000011 (/ - 1900)} days 

 = {365.25964134 + 0.0000000304 (/ - 1900)} days 

 = {346.620000 +0.00000036 (/ - i90o)}days 



{29.530588102 0.00000000294 (t i9oo)}days 

 {27.321660890 0.00000000252 (/ i9oo)}days 



Sidereal day (ordinary, two successive transits 

 of vernal equinox, might be called equinoctial 

 day) 



Sidereal day (two successive transits of same 

 fixed star) 



1920, Julian Period = 6633 



January i, 1920, Julian-day number = 2422325 



86164.09054 mean solar seconds 

 = 23 h. 56 m. 4.09054 mean solar time 



= 86164.09966 mean solar seconds 



Solar parallax = 8. 7958" 0.002" (Weinberg) 



8.807 0.0027 (Hincks, Eros) 



8.799 (Sampson, Jupiter satellites; Harvard observations) 



8.80 Paris conference 

 Lunar parallax = 3422.63" = 57' 2.63" (Newcomb) 



Mean distance earth to sun = 149500000 kilometers = 92900000 miles 

 Mean distance earth to moon = 60. 2678 terrestrial radii 



= 384411 kilometers = 238862 miles 



Light traverses mean radius of earth's orbit in 498. 580 seconds 



Velocity of light (mean value) in vacuo, 299860 kilometers/sec. (Michelson-Newcomb) 

 = 186324 statute miles/sec. 

 Constant of aberration = 20.4874" 0.005" 



20.47 Paris conference (work of Doolittle and others 



indicates value not less than 20.51) 



Light year = 9.5 X io 12 kilometers = 5.9 X io 12 miles 



Parsec, distance star whose parallax is i sec. = 31 X io 12 km = 19. 2 X io 12 m 



General precession 

 Obliquity of ecliptic 

 Constant of nutation 

 Gravitation constant 

 Eccentricity earth's orbit 



Eccentricity moon's orbit 

 Inclination moon's orbit 

 Delaunay's y = sin \I 

 Lunar inequality of earth 

 Parallactic inequality moon 



50. 2564" + 0.000222 (t 1900)" (Newcomb) 

 = 23 27' 8. 26" - 0.4684 (t - 1900)" (Newcomb) 

 = 9.21" (Paris conference) 

 = 666.07 X io~ 10 cm 3 /g sec 2 * o. 16 X io~ 10 

 = e = 0.01675104 0.0000004180 (t 1900) 



0.0000000000126 (/ 1900)2 

 = e-i = 0.05490056 (Brown) 

 = /= 5 8'43.5"(Brown) 

 = 0.04488716 (Brown) 

 = L = 6.454" 

 = Q = 124. 785" (Brown) 



Pole of Milky Way 



= R. A., 12 h. 48 m.; Dec., +27 



SMITHSONIAN TABLES- 



