XXXVI 
PRELIMINARY GENERAL CATALOGUE OF STARS FOR I9OO 
or the magnitude of both stars when the mean is given in the Catalogue; next the 
estimated distance in 1900; and the estimated position angle at that date. 
The general catalogues of Innes, Lewis, and Burnham have furnished the infor¬ 
mation herein adopted. Many of the statements of numerical data are followed with 
the remark, “binary,” “slow binary,” “rapid binary,” etc.; but in all cases where 
exact information is required one will, of course, recur to original sources or to the 
general catalogues mentioned. In the column of Remarks, “See Appendix” refers 
to notes in Appendix II, to which were transferred all comments upon individual 
stars too lengthy for insertion on the pages of the Catalogue. These notes, few in 
number, refer chiefly to peculiarities of motion. 
APPENDIX I. 
Immediately following the Catalogue is a list of stars within eight degrees from 
the pole for which computed places are given for dates subsequent to 1900. From 
these and for ordinary requirements the reader has the means for deriving with ease 
the predicted place for any date subsequent to 1900 and up to 1925 without a 
trigonometrical reduction. The places predicted in Appendix I were derived by 
trigonometrical computation with Newcomb’s constants. They were checked by 
mechanical integration, which operates also as a very fair check upon the accuracy 
of the computed values of annual and secular variations. These ephemerides lay 
no claim to more than substantial accuracy. 
The table given previously in the chapter on “Annual Variation, etc.,” at p. 
xxvii of this Introduction, was employed in the construction of the ephemerides, 
and it may be found convenient for purposes of verification. 
For Polaris and 8 Ursse Minoris an ephemeris for five-year intervals throughout 
the nineteenth century is also included. 
In interpolating, it will usually be necessary to take into account the third 
term 
This may be derived with sufficient approximation from the 
differences of secular variation. Designating by v x and v 2 two successive values of 
the secular variation separated by the interval r, we obviously have for the third 
term in right-ascension (and correspondingly for declination): 
(Centennial) - (^)(^) 
When t = 5 or 25 years respectively, we have: 
For 5 years’ interval, 
For 25 years’ interval, 
1 A 3 a 
6 Af 
In general, the numerator of the coefficient is 1000 and the denominator is 0.6 r. 
As an illustration, let it be required to compute the right-ascension of No. 185 
(=Br 74) for 1910. We have sec. var. for 1900, -M6019, and for 1925, +?6378. 
Hence the third term is: (+ *6378-^6019)= + 2 s .39 for 1912.5, about. 
