वेदों की प्राचीनता एवं काल-निर्णय / ओरायन (लोकमान्य बाल गंगाधर तिलक - खगोलीय वैदिक शोध)

THE ARCTIC REGIONS. 53
stationed at a place within the terrestrial tropical zone, once in
his course from E' to E, and again in his return, from E to E'.
The sun will also appear for some time to the north of the ob-
server's zenith, and for the rest of the year to the south. But
as the altitude of the sun above the equator is never greater
than 23½° or EQ, an observer whose zenith lies to the north of
the circle T'E, will always see the sun to the south of his
zenith, and the zenith distance of the sun will be greater and
greater as the observer advances towards the North Pole. But
still the sun will be above the horizon every day, for some hours
at least, to an observer whose zenith lies between T'E and AC.
To take a concrete in-
stance, let the observer
be so stationed that his
zenith will be at C, that is,
on the extreme northern
latitude of the temperate
zone. Then his celestial
horizon will extend 90° on
each side, and will be re-
presented by T''CT, and
the sun moving along the
ecliptic E'E will be above his horizon, at least for some portion
of day, during the whole year. But as the observer passes into
the Frigid zone, the sun during his annual course will be alto-
gether below the horizon for some days, and the maximum
limit is reached at the North Pole, where the sun is below the
horizon for six months. We may, therefore, state that the dura-
tion of the night, which is six months at the Pole is gradually di-
minished as we come down from the Pole, until, in the temperate