( 355 ) 
wy = PS uw =angle made by the total proper motion « with the 
declination circle; 
x==PSQ=angle made by parallactie proper motion with th e 
declination circle ; 
v = component of total proper motion in direction SQ; 
r = component at right angles to the former (sign same as that 
of sin(y—w)); 
1) p=Z-wp=usSQ=angle made by w with the parallactic 
proper motion; 
h = linear motion of the solar system in space; 
_g= distance of the star to the solar system. 
We have: 
Ber : ; 
(2) — sin À = parallactic proper motion of star S; 
Q 
Moreover let : 
v (fig. 2) = peculiar proper motion of S; 
a' the angle made by this peculiar proper motion with the 
parallactic. 
We then have the following relations : 
(3) v= fecos(y—w) = U Cos p 
(4) 7 =u sin(y—yw) = U sin p 
ee eae dz 
34 = — an 
(5) 
dures Ox 
oo re OD 
dr Zr 
gd. B 4 
(6) 
meis hg | dye 
Mm do 
3. Stars in a very limited part of the sky. First we consider 
only a group of stars lying so close together that we ean practically 
assume that they are all at the same point of the sky. 
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