292 



THE SAYRE OBSERVATORY. 



it represents more closely the actual state of the celestial sphere, it is very desirable 

 that we should be able to refer our coordinates to that system. This may be very readily 

 done by employing the formula) and tables given by Newcomb for passing from one 

 system to the other. These are reproduced here for the convenience of any wishing to 

 make the change. The reduction of the declinations to the system of Boss is also 

 included. 



In what follows N refers to the system of Newcomb, 

 A refers to that of Auwers. 



On page 15G of Newcomb's memoir is given for the difference of the Equinoxes 



N = A -I- -.006 + ".00100 (2'— 1875) 



Combining this with the difference depending on the Declinations, page 165, the 

 reduction in Eight Ascension for any time T has the form 



(T— 1875) 



N = A + Acs + A/i 



100 



with a similar expression for the Declination. 



In the table, divisions A and B give the data for reducing the Bight Ascensions and 

 Declinations respectively from the system of Auwers to that of Newcomb ; C for 

 reducing the declinations to the system of Boss. 



Declination. 



A 



B 



O 



Acs 



A,,, 



Arf 



A/,,' 



A<5 



Aft' 



+ 85° 



1 



s 



— .00 



ft 



+ .37 



— .04: 



-1- .30 



80 



— .017 



+ .119 



+ .03 



+ .45 



— .07 



+ .30 



75 



— .008 



+ .127 



+ .04 



+ .40 



— .10 



+ .27 



70 



— .000 



+ .129 



+ .02 



+ .32 



— .13 



+ .10 



65 



-|- .004 



+ .127 



+ .03 



-j- .27 



— .14 



— .00 



00 



+ .005 



+ .124 



+ .09 



+ .20 



— .10 



— .10 



55 



+ .005 



+ .123 



+ .19 



+ .32 



— .04 



— .10 



50 



+ .002 



+ .128 



+ .22 



+ .36 



+ .04 



— .10 



45 



— .014 



+ .111 



+ .30 



+ .09 



+ .07 



— .35 



40 



— .012 



-[- .109 



-f .32 



— .72 



+ .08 



— 1.20 



35 



— .009 



+ .096 



+ .29 



— .80 



+ .06 



— 1.33 



30 



— .004 



+ .090 



+ .20 



— .81 



+ .05 



— 1.22 



25 



+ -004 



+ .091 



-|- .24 



— .85 



+ -.00 



— 1.18 



20 



-|- .000 



.093 



4- .24 



— .94 



+ .09 



— 1.27 



15 



+ .009 



+ .094 



+ .31 



— 1.00 



+ .15 



— 1.30 



10 



+ .011 



-|- .098 



+ .36 



— .98 



+ .18 



— 1.31 



+ 5 



+ .012 



+ .103 



+ .38 



— .92 



|- .19 



— 1.24 







+ .012 



+ .108 



+ .39 



— .80 



+ .20 



— 1.10 



— 5 



+ .012 



+ .113 



+ .42 



— .75 



+ .23 



— 1.14 



— 10 



+ .010 



-|- .113 



+ .55 



— .80 



+ .34 



— 1.25 



— 15 



+ .010 



-f .115 



+ .74 



— .72 



+ .48 



— 1.30 



— 20 



+ .009 



+ .116 



+ .89 



— .54 



+ .58 



— 1.30 



— 25 



+ .009 



+ .125 



+ .99 



— .44 



+ .00 



— 1.40 



