STELLAR PIIOTOGRAHIY. 



J17 



TABLE V. 



No. 



Designation. 









Rendu a Is. 









«k^ V^# 



I. 



s. 



+ 0.06 



II. 



j in. 



IV. 



v. 

 -0.01 



VI. 



«. 



0.00 



VII. 



349 



Atlas 



+ 0.07 



-0.03 



«. 



-0.03 



+ 0.01 



353 



Pleioue 



0.00 



+ 0.02 



-0.03 



-0.(14 



+ 0.1O 



+ 0.O1 



-o.oc 



14G 



Me rope 



+ 0.10 



-d.04 



-0.(>4 



-0.01 



+ 0.07 



-0.03 



+ 0.1" 



66 



Elect ra 



0.00 



-0.06 



+ 0.03 



+ 0.08 



-0.03 



+ O.04 



0.00 



62 



Celjeno 



-0.13 



- 0.01 



+ 0.13 



+0.01 



+ 0.04 



-o.ll 



+0.08 



115 



Mai a 



+ 0.06 



+ 0.03 



-0.08 



+0.01 



-0.04 



+ 0.04 



+ 0.' :; 



79 



Taygeta 



-0.21 



+ 0.07 



-0.01 



-0.04 



-0.01 



+ 0.O7 



-0.1 1 



121 



Asterope 



+ 0.11 



-0.17 



+ 0.10 



-0.01 



+ 0.01 



-0j - 



-0.07 



227 



Alcyone 



+ 0.14 



+ 0.i '3 



-0.06 



+0.03 



-O.10 



+ 0.08 



+0.11 



349 



Atlas 



-0.06 



+ 0.01 



0.00 



+0.03 



-0.03 



+ 0.01 



-0.04 



The average values of these residuals, taken 



without regard to sign, arc 



0.087, 



0.051, 0.051, 0.029, 0.044, 0.047, and 0.059, in the seven columns respectively. The 



first of these values is decidedly greater, showing that it was difficult to Bel with 

 accuracy on the centre of so long a line as that produced when the exposure lasted 



for two seconds 



The last value is also somewhat greater, owing to the difficulty of 



r 



determinins: the end of a trail. 



The difference is, however, much less than was 

 anticipated. The mean of all the residuals is 0.053, or, if we use only l lie intervals 

 between short exposures and reject the first and last values, 0.044. Since all of 

 these values are found from the difference of two settings, we must divide by the 



We thus 

 ii ur is found 



n 



of 



obtain the average d 



f a single sotting 



obtain the values 0.037 and 0.031. The probable error of 

 by multiplying these values by 0.85, which gives ±0. 

 has been reiected for discordance, and no change made 



031 and ±0.02G. No Betting 



- 



that the seventh setting on 



Maia was recorded 54. G8 



w a - 



20 rd except 

 d to mean 



54.03 



This setting 54.685 would render the preced 



and foil 



•- 



values so 



large that they would have to be rejected for discord 



One would be increased 



and the other diminished by S .70 



As shown in the Table 



assumed value 



th 



duals +0\04 and +0\03 



To s 



how 



far the deviations were d 



of 



*-: 



O 



•- 



of Cel 



d 



gave an average 



deviation of ±0 S .015 and a probable error of ±0'.013. These 



uld doubtless be reduced by the use of a highe 



fying pow 



that employed being much too low. The probable 



of 



O 



