no 



Tables 89-91 .-ASTRONOMICAL DATA. 



TaWe 89.— Planetary Data. 



* Earth and moon, t Relative to earth. Inclination of axes : Sun 7°. 25 ; Earth 23^.45 ; Mars24°.6; Jupiter 3°.i; 

 Saturn 26°. 8; Neptune 27°. 2. Others doubtful. 



Table 90. — Equation of Time. 



The equation of time when + 's to be added to the apparent solar time to give mean time. 

 When the place is not on a standard meridian (75'th, etc.) its difference in longitude in time 

 from that meridian must be subtracted when east, added when west to get standard time (75'th 

 meridian time, etc.). The equation varies from year to year cyclically, and the figure following 

 the J- sign gives a rough idea of this variation. 



Table 91. — Miscellaneous Astronomical Data. 



Apex of Solar Motion : 



From proper motions, R. A.igio = 17 51"*, Dec.i8io= + 31.4 (Weersma, Gron. Publ. 21.) 



From radial velocities, R. A. 1900 = I7*54"S Dec.1900^-}- 25.1 (Campbell, Lick. Bull. 196.) 

 Velocity = 19.5 Km. per sec. (Campbell.) 



Nearest star so far as known: a Centauri, parallax =: 0.759" (Gron. Publ. 24) distance = 4.3 

 light years. 



Stars of both greatest proper motion and greatest radial velocity so far as known :* Cordova, 

 V243; proper motion = 8.70" in position angle 130° radial velocity + 242 Km. per sec. (Camp- 

 bell, Stellar Motions, 1913). Parallax = 0.319" (Gron. Publ. 24, also proper motion). Distance = 

 10.2 light years. 



Average velocities with regard to center of gravity of the stellar system, according to Camp- 

 bell (Stella'r Motion, 1913) : 



Type B Stars : 6.6 Km. per sec. Type G Stars : 15.0 Km. per sec. 

 •' A " 10.9 " " " " K " 16.8 " " " 



" F " 14.4 « " " " M " 17. 1 " " " 



Sun's magnitude =: — 26.5, sending the earth 90,000,000,000 times as much light as the star 

 Aldebaran. 



Ratio of total radiation of sun to that of moon about 100,000 to i 



light 



400,000 to I 



Langley. 



* Lalande, 1966, R.A.,gjQ i''3"'.9, Dec.jg,^ 61°. 4' in 1913 was found to have a radial velocity (of approach) of 326 

 Km. per sec. (Mount Wilson Solar Observatory.) 



Smithsonian Tables. 



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