CHAPTER XI.—V DELPHINI. 
159 
The striking characteristics of the star’s variation are its great range, but 
little less than 10 magnitudes, and its rapid rise to maximum, best shown at 
epoch 6. The curve at maximum is usually quite sharp, though this is not con¬ 
firmed by the observations of Reed at Harvard in 1891, published in Astronomical 
Journal, 13 , 63. Further reference to these observations will be made later. 
The shape of the curve near minimum can be inferred by combining the observa¬ 
tions on the descending branch of the curve following maximum 6 in 1900, and 
those on the ascending branch preceding maximum 8 in 1902. Combining 
these observations with the limit of vision when the star was not seen, the curve 
at minimum is fixed very nearly as drawn. 
PERIOD OF VARIATION. 
The elements of maximum given by Chandler in his Third Catalogue and 
retained in his “Revised Elements,’’ published in 1904 
1890 December 20 (2411722) -f 540 d E. 
are based on six maxima between 1890 and 1899, fitting the first five maxima 
very w^ell, but requiring a correction of - 34 days for epoch 6, and about - 80 
days at epoch 9. The observations now available are represented better by the 
elements, 
1891 January 14 (2411747) +529 d E. 
This w r as obtained by using only the best observed maxima, 2, 4, and 6, and 
shortening the period thus obtained 2 days on account of the last maximum 
in the light-curve, No. 9. 
In this connection tw r o sets of observations require separate consideration. 
First, Mrs. Fleming’s measures from the photographs, published in Astronomischc 
Nachrichten,\ 27 , 5, showing that the star was invisible, less than 10th magnitude, 
on six dates from June 30 to October 28, 1890, and photographically 9.3 magni¬ 
tude, November 28; 8.6 on December 19; 9.0 December 20, and 8.7 on December 
22. Considering the small number and range on these plates it is thought that 
no violence is done to them by assuming the date of maximum to be as late as 
January 14. Second, a set of observations made at Harvard by W. M. Reed, 
and published in Astronomical Journal 13 , 63, are not in accord with the above 
elements and mean light-curve. They are given in Table 97, with the addition 
of three columns giving respectively the Julian day, the number of days after 
the preceding maximum as calculated by the foregoing elements, and the cor¬ 
responding magnitude from the mean light-curve. 
