of {he Moon from the Sun or a Star. 58 



\pp. Dist. J=38«52'...sine. 9.7976 9.7976 d— S** =5G°52' (/ 



App. alt. s=4S 14 g- cosec. 0.38*8 0.3848 Tab. xvii 58 o9 



JApp.alt. m=53 4 / sec. .0570 S. sec 0.4187 Tab. xix 2737 



lB=d+s-{-m = l55 to Tab.xvii.lo^. 1.8112 Tab.xixlog. 2266 Cor. 1 1 36 



S 67.35lstCorr.P.L. 2.0506 2d. corr.P.L. 8277 Cor. 2 26 46 



Tab sx 29 



S Qc d=zf 28.43 



S-_s_^ 24.21 



True distance 38 47 27 



Thus we see tliat this method is quite short, and it has the inestL 

 mahle advantage of being free from a variety of cases in the op- 

 plication of the corrections, since all the terms are additive. 



The two neglected terms BC + (MS — MC) may be comput- 

 ed in the following manner. We have BC = BS. sin. BSC 



3S. sin MBK nearly ; and sin. MBK = -^ nearly, hence BC 



^^•^^^ K„i. 1 2. COS. rf 2. COS. c? J. ... , . _ 



~^i^^' ^""^ liin = 2. sia. d. coid = ^hT^rf" divi*^i°s ^y sin- ^ we 



1 1 2. cot. ^ c. , J - 1 



sin £^ 



S. y ^ cot rf. cosec 2 d^ which being substituted in BC^ it becomes 



n 



BC = S. BS. \J±MW\ coLd, >f cosec. g fZ, and this may be cal- 

 culated by means of the Tables E, F, G subjoined. In Table E 

 the argument at the top is 60' — SA, at the side, the first correction 

 S A -f- AB, the corresponding number is the value of BS 

 /yfSA' — AB^ in minutes = E. In Table F the argument at the 



top is E, and at the side the third correction 18^ ± -i MK^ cot. d, 

 the tabular number corresponding being 



F = T V iBSV^. MKr. cot. d] =^sjK sJi.MK\coid. expres- 



sed in minutes. Then in Table G, the argument at the top is d, and at 



the side F, corresponding to which is the expression of 



8 



4» 



