28 



PREDICTION OF OCCULTATIONS. 



<p 



Log^ 



Log .5 







9.9971 



0.0000 



10 



9.9971 



0.0000 



20 



9-9973 



0.0002 



3° 



9-9975 



0.0004 



40 



9-9977 



0.0006 



50 



9-9979 



0.0009 



60 



9.9982 



O.OOI I 



7° 



9.9984 



0.0013 



rsintp' = 7lsin<p 

 rcos<?>' = Bco3(p 



a = rcos<p'sin(7i — d) 

 b = r cost?)' cos (7« — d) 



loffX = 9-4192 



u = a 



V = rsincp'cosi? — hsinD 



msialf = J) — u 

 mcosM = q — v 



u' = JA 



i/ = aAsini? 



«sin iV = y — u' 

 MCOsiV= g' — V 



loff>t = 9-4350 



0084* = 



msm{3f—N) 



(2 = 270°— iVq: 4' 



t = cos(M—JSf)=f 



n n 



Upper signs for Immersion ; under signs for Emersion. 



c sin C = u -i- 1 u' 

 c cos C^=v -i- tv 



Mean Solar Time of the Star's apparent contact with the moon's limb : 



= T-d+t 

 Angle from North Point = Q 

 Angle from Vertex = V 



The angle 4- is to be taken out positive and less than 180°. If logmsin(i!f — JV) 

 be greater than log Jc, cos 4^ will evidently be greater than 1, or impossible, and there 

 will be no occultation, except in some rare instances where the moon's Hmb passes 



