Sixty-five Stars near 61 Gygni. *ll 



24. Table IX. — Column three contains the mean of the final 

 position-angles of Table VI, and column two the mean of the dis- 

 tances, converted to seconds of arc by the scale value 28. "0124. 

 These are followed in columns four and five by the differences of 

 right ascension and of declination derived by aid of the formulae : 



Logarithms for Plates of 

 61 1 Cygni only. 

 n — <r sin fi- 

 m = a cos 7T 



P = sec d = [o. 104215] 



Q = [4.685575 ] tan d sec d = [4.6846 ] 



E = [8.89403,, ] tan 2 d sec 6 = [8.7878,, ] 



S = [8.89403 ] sec 6 (1 + 3 tan 2 d) = [9.4528 ] 



T = [4-384545n] tan d = [4.2793,,] 



U= [8.593QO n ] (1 -f- 3 tan 2 d) = [9.0475,, ] 



V = [3.57960a ] sec d tan d (1 -f- 3 tan 2 d) 

 W= [3.57960 ] sec d tan d (2 + 3 tan 2 6) 



a' — a = Pn -\- Qnm + Bn 3 + Snm 2 + ( Vn s m -f- Wnm 3 ) 

 6' — d = m + Tn 2 + Unhn 



where a and - are the final corrected mean distance and position- 

 angle respectivel}* of the star whose a' and 8' are desired. It was 

 found also that the terms in V and FT were not needed, since they 

 are so nearly equal and have contrary signs. 



In column six is the number of plates on which the image of 

 the star was impressed ; though it is proper to state that the 

 given position is the result of at least twenty measures of distance 

 and twelve of position-angle for each plate recorded in this column. 



In columns seven and eight are the Durchmusterung number 

 and magnitude for as many of the stars as could be identified. A 

 few of those found in the Durchmusterung but not found on 

 these plates, though of much brighter magnitude than many 

 which are on the plates, no doubt are missing because of their 

 color ; as obviously light from reddish stars affects the plate but 

 little, though optically it may appear quite bright. 



25. Table X is on pages opposing Table IX and gives the 

 right ascensions and declinations of each star. These were ob- 

 tained by adding the a 1 — a, 8' — 8 of Table X to Auwers's posi- 

 tion of 61 1 Gygni reduced to 1873.0 with the constants given in 

 the Fundamental Catalog : 



a = 21" ox"' 12*329 1 i873 _ o 

 d = 38° 07' 33.40 J 



