OEBIT ELEMENTS COMET I., 1899, (SWIFT). 181 



Elements II, (Dr. Stichtenoth.J 1 

 T = 1899 April 12-97774 G.M.T. 



o / // 



w = 8 41 29-70 ) 

 Si = 24 58 15-10 [-1899 

 i = 146 16 8-50 J 

 Log? = 9-5137940 

 q = 0*326432930 



Equations for Co-ordinates. 



x = [9-9877266] r sin (v + 77 31 14-16). 

 y = [9-9962519] r sin (v + 165 41 50-06). 

 z = [9-4288656] r sin (v + 47 26 12-86). 



Observations. — The observations used in forming the definitive 

 positions of the comet ; have been obtained from the pages of the 

 Astrononiische Nachrichten, Comptes Bendus, and the Astronomical 

 Journal, but in several cases they have been communicated in 

 manuscript previous to publication. 



As most of the observations used are comparisons with stars, 

 the true positions of the comet depend in a great measure upon 

 the accuracy of the adopted co-ordinates of these comparison stars. 

 Before deciding the co-ordinates of the comet, the star places have 

 been investigated, and to several, proper motion has been applied; 

 they were also reduced to the A.G. system, the quantities for this 

 purpose being interpolated from the tables of Professor Auwers, 

 A.N. 3195-96, 3413-14. 



The reduction of the mean places of the stars to apparent has 

 been made by the usual formula, adopting the quantities of the 

 Nautical Almanac. In finding the parallax of the comet in right 

 ascension and declination the value 8 '"80 has been used for the 

 equatorial horizontal parallax of the sun. 



The following table contains the results of the comparison of 

 the observations with the ephemeris ; also the weights adopted in 

 forming the normals, these depend on the number of comparisons 

 made and combined to form a completed observation ; in a few 

 instances the number of comparisons has not been given by the 

 observer, in these cases the computer has used his discretion. 



1 Astronomische Nachrichten, No. 3567. 



