ON THE PLANET CERES. 287 



is — As the fine of the planet's elongation from the fan : — in to the 

 angle of commutation (or difference between the helio. longi-' 

 tudes of the planet and of the earth) — So is the tangent of the 

 geocentric lat : i$ to the tangent of the heliocentric latitude. 



From this account of the means neceflary to be ufed in From the pre- 

 afcertaining the precife nature of the orbit of a newly dif- "^"^^ 

 covered planet, it will be naturally inferred that the elements no elements of 

 already afligned to the orbit of the new planet Ceres cannot the new planet 

 i ii • i 111 «i can y et be ac- 



be very accurate, allowing them to be duly proportioned to curate. 



one another, becaufe an error in any one of its elements 

 renders all the reft erroneous ; and there has not yet elapfed, 

 probably, much more than one-fourth of an entire period fince 

 its difcovery, nor has it yet been in the moll eflential portions 

 of its orbit for affording the beft data. Hence a continuation 

 of accurate reports concerning this planet ought to be publicly 

 recorded from time to time, in order that a comparifon of 

 different and diftant obfervations may afford the requifite data 

 for ultimately fettling its elements with accuracy. I fhall 

 therefore make no apology for laying before your readers an 

 extract from a letter of Baron Von Zach to his friend and cor- 

 refpondent, Mr. Edward Troughton, mathematical inftru- 

 ment-maker, of Fleet Street, who has very obligingly put 

 it into my hands, with permiffion to make what life of it I 

 may think proper. The letter is unufually long, and full of 

 interefting matter ; but I fhall confine myfelf, in this commu- 

 nication at leaft, to thofe parts of it which principally relate 

 to the new planet, and the fubje£ts connected with it. 



Extract of a Letter from the Baron Von Zach to Mr. Edward Letter from Von 

 Troughton. Zach * 



Gotha, January 28, 1802. 

 " ********** YOU have heard perhaps, dear friend, Re-difcovery of 

 that I was fo lucky as to difcover again Mr. Piazzi's planet, the P lanet Ceres « 

 called now, in honour of the king of Naples, Ceres Ferdi- 

 ndndea. I found this little planet firft on the 7th of December 

 laff. year, juft between the head and the north wing of Virgo, 

 in 178° 33f' right afcenfion, and 11° 41 J' declination N. 

 An aftronomical friend of mine, Dr. Olbeis, in Bremen, 



found 



