THE DETERMINATION OF TRANSATLANTIC LOWITOI-1 



A 



US 



Formula used in the Computation of Instrumental and Chck Corr. on». 



T+AT+ r (r being the correction in time for error* in azimuth. I, t el, equal. u 



<f> 



d 



M 



f 

 P 



a- 



R 



h 



Star constant A 



Star constant B 

 Star constant C 



k 



Bb 



o 



T 



t 



AT 



(O 



Cc 

 Aa 



G> 



VOL. IX. 



of pivots, and collimation.) 



c 



sin ((f) — 8) _ cos (</> — 8) 



a - - \- b ^ . ' + 



cos 8 cos 8 



cos 8 



la + W ± ft,* (a) being the azimuth 



constant, (6) being the level constant, and (c) being the collimation eonsfett. 



geographical latitude of the station, 

 right ascension of the star. 



the 

 the 



the declination of the star, 

 the mean of the observed tallies, 

 the mean of the equatorial thread-intervals 

 the correction for rate, and its log is 0.000005 for a gain of 1 

 a mean time clock. 



daily: 0.00119 for 



the sine correction when star is near the pole: log a being additive to log /\- when 



F sec 8 is less than 2 m# it may be neglected, 

 i^sec 8. o". p; and is to be added to M to obtain the time of transit over the m« 



of all the threads. 

 = the level constant in time, corrected for inequality of pivots: it is positive for W. 



end high. 



sin ((f) 



5) 



cos 8 

 cos (<p — 8) 



cos d 



sec 8. 

 180° 



pol 



A is positive, except for stars between the Zenith and North Pole. 

 B is positive, except for stars at lower culmination, 



C is positive, except for stars at lower culmination, 

 the diurnal aberration = - .021 cos <p sec 8. 



minations. 

 correction for level and inequality of pivots. 



T+Bb + 



( 



upper, (-f-) »n lower cul 



all 



At 



t 



correction of the clock. 



+ Aa± Cc. 



correction for collimation. 

 correction for azimuth. 

 co =F Cc, upper sign for lamp west. 

 The collimation constant (c) is determi 

 is to be obtained from the equation 



ined from 



en circnm polar stars, aad 



L 



t 



O) 



o> 



2 O. 



correspon 



the value of o>„ for the several stars to an arbitrary time 

 correction for daily rate. Calling this reduced value (-0), 



are applied, reduce 

 T , bj applying the 



(« ) 



0)0 24hrs. 



X daily rate 



♦ 



Mayer's formula, corrected for inequality of pivots and aberration 



62 



