CHAPTER XII.—Z CASSIOPEIA. 
173 
Table 107.—8518 Z Cassiopeia. Observed Maxima and Minima. 
Elements of maximum. 1898 Nov. 22 (J. D. 2414617) + 492-1 E. M-m= 173 «. 
Maxima. 
Minima. 
xi 
Date. 
Mag. 
X5 
Date. 
Mag. 
u 
Corr. 
Wt. 
Corr. 
Wt. 
0 
w 
Calendar. 
J. D. 
H. 
P. 
w 
Calendar. 
J. D. 
H. 
P. 
0 
1903 Nov.27 
4622 
10.7 
10.6 
+ 5 
9 
I 
1899 Oct. 9 
4937 
me 
4- 1 
2 
1 
1900 Apr. 3 
5H3 
10.20 
10.09 
+ 4 
35 
2 
1901 Feb. 24 
5440 
me 
— 12 
2 
2 
1901 Aug. 18 
5615 
me 
+ 14 
1 
3 
1902 June 2 
5903 
me 
-17 
6 
4 
1904 Apr. 11 
6582 
me 
“ 3 
4 
5 
1905 Feb. 11 
688S 
15.18 
1507 
“ l6 
15 
The mean light-curve was formed from the observations up to 1905 June 
27, and gives the mean period 492 days. The last minimum, 1905 February 16, 
is the only one well covered by the observations. The five comparisons between 
1905 January 24 and April 11 were made with difficulty, owing to the low posi¬ 
tion of the field and the faintness of the variable, which seems to have been fainter 
than the star n. On account of the difficulties mentioned, the stars n and ^ were 
taken for the variable and n, but the real brightness of the variable is shown by 
the observations of January 3 and April 30. The comparisons made in May, June, 
and July show an unmistakable halt in the rise between the 13th and 14th magni¬ 
tude, followed by a sudden increase of more than one magnitude between August 
6 and 19. The corresponding rise in February, 1900, was less rapid. 
The period 492 days satisfies the present series of observations, and there 
seem to be no others for comparison until Hart wig’s are published. 
