206 



DETERMINATION OF AX ORBIT FROM 



[BOOK 11. 



We join directly to this calculation the determination of the longitude and 

 latitude of the zenith of the place of observation in the three observations : the 

 right ascension, in fact, agrees with the right ascension of Juno (because the 

 observations have been made in the meridian) but the declination is equal to the 

 altitude of the pole, 51 28 39&quot;. Thus we get 



Now the fictitious places of the earth in the plane of the ecliptic, from which 

 the heavenly body would appear in the same manner as from the true places of 

 the observations, will be determined according to the precepts given in article 72. 

 In this way, putting the mean parallax of the sun equal to 8&quot;.6, there results, 



The reduction of the time is added, only that it may be seen that it is wholly 

 insensible. 



After this, all the longitudes, both of the planet and of the earth, are to be 

 reduced to the mean vernal equinox for some epoch, for which we shall adopt 

 the beginning of the year 1805 ; the nutation being subtracted the precession is 

 to be added, which, for the three observations, is respectively 11&quot;.87, 10&quot;.23, 8&quot;. 8 6, 



