ON THE NEW PLANET CERES. &£ 



3. The fynodic revolution correfponding to this motion is 

 456 d 10 h 22 m . 



4. The time of oppofition could not be on the 17th of 

 March as dated in this letter, but about the 23d, as has been 

 mentioned before, becaufe it was on that day that the diffe- 

 rence of the right afceniions of the fun and Ceres was 1 80°, 

 even according to the Baron's own table : the error feems to 

 have arifen from reckoning the point diametrically oppotite 

 Ceres to be nearly two degrees Jhort of the equinoctial point, 

 wiftead of the fame quantity over, when the right afcenfion of 

 Ceres was about 182°: the other circumftances alfo depen- 

 dent on the moment of oppofition mull therefore be attributed 

 to the 23dinftead of the 17th. 



5. On receiving thefe laft corrections of Dr. Gaufs I was Caufe of the- 

 at firft furprifed to find fuch a trifling alteration made with the g^emof" 

 greateft equation and correfponding eccentricity, after the fome dedudions 

 error which I was confident I had deteaed; but I have now of the author, 



. r P r and the element* 



found out the caufe of the apparent difcrepancy, which fome f Mr. Gaufs. 

 ftrefs has been laid upon ; the mean diftance and eccentricity, 

 I now perceive are, contrary to the ufual mode of expreflion, 

 given in terms of different denominations: the mean diftance has 

 been given in terms which fuppofe the radius of the earth's 

 orbit to be unity, and the eccentricity is given in terms which 

 fuppofe the radius of the orbit of Ceres to be unity, inftead of 

 its proportional radius 2,769964. Profeflbr Robifon on the 

 contrary, in his approximate elements of Georgian exprefied 

 the mean diftance and eccentricity in terms of the fame deno- 

 mination, which is alfo done by Lalande, Vince, and other 

 eminent aftronomers with refpect to the other planets. Let us 

 try now what the greateft equation will be by the elliptic hy~ 

 pothefis, when unity is made the radius of the orbit : 



As the aphelion diftance (1+,08140) 1,08140—4,03383 

 Is to perihelion diftance (1— ,08140) 9186—3,96313 ' 

 So is tang : of 46° \ mean anom : - 1 0,0*556 



4,00869 

 To tang : \ eq. anom : 43° 20' 33,6" - 4,03383 



9,97486 

 Then 48* 20' 33,5" + 2 = 86° 41' 72"; and 92° — 86° 

 41' 7,2" = 9° 18' 5,28" is the greateft equation. 



2 Alfo- 



