LOOKING BEYOND THE WORLD. 
141 
sky into two equal parts. The sun comes to this 
meridian at noon. As the earth turns, this meridian 
is constantly changing. The meridian of any place 
at any time is the one which passes exactly overhead. 
The celestial equator is the great circle that crosses 
the meridian circle at right angles half-way between 
the north and south poles. On the first day of spring 
the sun moves along the celestial equator in the 
heavens. If an observer stand on the earth’s equator 
his meridian passes north and south directly overhead, 
and his celestial equator passes directly overhead east 
and west. 
Right ascension is the longitude of the star, that 
is, the distance of the star west of the meridian pass¬ 
ing through the constellation Aries. It is now usu¬ 
ally reckoned in hours, not degrees. The declination 
of a star means its distance north or south of the 
celestial equator, expressed in degrees. Thus we may 
observe that a star is in R. A. 2 hrs. 45 min. 30 sec., 
and K D. 30° 25' 40". 
With this preparatory information, let us go forth 
some clear night and choose an eminence, if possible, 
from which to watch the motions of the stars. Stand¬ 
ing with your face to the north, you may see the 
Dipper at your right, at about eight o’clock, if the 
month be January, or the Great Bear to the north¬ 
west and the Little Bear in front, looking toward 
your zenith. (See Book II of this series.) Also no¬ 
tice the position of other clusters and the several 
bright stars in view. Another view two hours later 
will show that all the stars have changed position, ex- 
