234 



CATALOGUE OF POLAR STARS. 



In 



manner, the folio 



eight years. 



o 



of a and B were computed for 



of 



Date. 



1755 

 1763 

 1771 



1779 

 1787 

 1795 

 1803 

 1811 

 1819 



1827 

 1835 

 1843 

 1851 



h. m. s. 



4 45 55.203 



4 56 19.577 

 6 59.542 



5 17 52.998 

 5 28 57.519 

 5 40 10.397 



5 51 28.695 

 2 49.333 



6 14 9.166 

 6 25 25.071 

 6 36 34.034 

 6 47 33.225 

 6 58 20.073 



// 



+ 89 1 1.38 



+ 89 1 48.90 



+ 89 2 29.33 



+ 89 3 2.41 



+ 89 3 27.93 



+ 89 3 45.70 



+ 89 3 55.62 



+ 89 3 57.66 



+ 89 3 51.70 



+ 89 3 37.84 



+ 89 3 16.18 



+ 89 2 46.91 



+ 89 2 10.16 



Date. 



a 





8 







k. m. s. 



O 



/ 



// 



1859 



7 8 52.315 



+ 89 



1 



26.19 



1867 



7 19 8.026 



+ 88 







35.27 



1875 



7 29 5.631 



+ 88 



59 



37.69 



1883 



7 38 43.913 



+ 88 



58 



33.76 



1891 



7 48 1.994 



+ 88 



57 



23.81 



1899 



7 56 59.309 



+ 88 



56 



8.17 



1907 



8 5 35.579 



+ 88 



54 



47.17 



1915 



8 13 50.774 



+ 88 



53 



21.14 



1923 



8 21 45.073 



+ 88 



51 



50.40 



1931 



8 29 18.828 



+ 88 



50 



15.24 



1939 



8 36 32.527 



+ 88 



48 



35.97 



1947 



8 43 26.768 



+ 88 



46 



52.87 



1955 



8 50 2.231 



+ 88 



45 



6.21 



The places for single years will be easily obtained by successive interpolations 

 to the middle, by means of the formula (see Chauvenet, Vol. I. p. 88), 



jpi 



4 (F + F') 



I 



rV L c 4) 



T(T 



& (/o 



Ac)]] 



(9) 



Bessel has given a method (see Wolfers, Tab. Reg., pp. lii, liii) by \i 

 ies of a and S' may be computed from an approximate value of 

 Let 



true 



a . 



a/ = nn approximate value of a', 



A/ = ** - (z> 



V). 



From Napier's first and second Analogies, 



tan i (d' 



cotan I (<$' 



«) 



5) 



cos J (A/ + A) 



cos \ {AJ 



A) 



tan \ d 



sin \ (A/ + A) 



sin I (A^ 



A) 



tan \ 6 



(10) 



(11) 



Let the variations in 

 have the following desio- 



the 



thms of the given functions for a change of 1 



// 



