68 CELESTIAL MECHANICS: LEUSCHNER 



(718) ERIDA, 1911 MS. 



Discovered by Palisa 1 at Vienna, 1911, September 29. 



Preliminary Elements A, and an ephemeris based on observations 

 1911, September 29, October 13, and October 28, are published by 

 Cohn. 2 These elements were used by the B. J. 1915 and 1916. 



New Elements B were obtained by Strehlow 3 from observations 1914, 

 February 28, March 18, and March 29. The method of the variation 

 of the distances was utilized so that observations of 1911 and 1914 

 were well represented. 



A correction of +1".5 to /A was applied in order to represent observa- 

 tions of 1904 for (1904, OD) which is supposed to be identical to 

 (718) Erida. 



As a test of Leuschner's Short Method for computing orbits, 4 Mundt 5 

 has published two sets of elements C and D, which are based on the 

 observations used by Cohn. 2 



For the purpose of comparison, ephemeris places were computed 

 from Cohn's Elements A, Strehlow's Elements B, and Mundt's Ele- 

 ments C. 



1917 G. M. T. a 8 



Oct. 22.5 2 h 56 m 3 +17 09' Elements C. 



Oct. 22.5 255.9 +17 07 Elements B. 



Oct. 22.5 253.5 +1656 Elements A. 



Dec. 1.5 225.3 +15 39 Elements C. 



Dec. 1.5 225.1 +15 36 Elements B. 



Dec. 1.5 222.9 +15 24 Elements A. 



-Ne comparison with observations in 1917 has been made. 



Strehlow's Elements B have been published and utilized by B. J. 

 (Kleine Planeten) since 1915. An observation by Palisa 6 on 1919, 

 January 6, gave corrections to the ephemeris as follows: Aa l m .7 

 AS 3'. 



The object of Mundt 's work was to test the possibility of deriving 

 by properly chosen methods as satisfactory elements from a single 

 opposition as are ordinarily obtained from at least two oppositions. 

 This result was realized in this case. His work was duplicated by 

 Miss Easton 5 on a slightly different plan of removing the residuals. 

 Elements D. 



REFERENCES 



1 A. N. vol. 189, p. 295. 4 L. O. Pub. vol. vii. 



3 A. N. vol. 192, p. 421-423. 6 L. O. Bull. No. 302. 



'B. J. 1917, p. 36 and 106. 'E. Z. der A. N. 1919, No. 561. 



