Artic Home of the Aryans by Lokamanya Bal ... - Mandhata Global

48
celestial North Pole. When the observer was stationed at the
terrestrial North Pole, his zenith coincided with P, and his horizon with
the celestial equator, with the result that all the stars in the dome
Q'PQ revolved round him in horizontal planes. But when the zenith is
shifted to Z, this state of things is at once altered, as the heavens will
revolve, as before, round the
line POP', and not round the
zenith line ZOZ'. When the
observer was stationed at the
North Pole these two lines
coincided and hence the circles
of revolution described by the
stars round the celestial Pole
were also described round the
zenith-line. But when the zenith
Z is different from P, as in the
figure, the celestial horizon of
the observer will be H'H, and
the stars will now appear to
move in circles inclined to his
horizon, as shown in the figure
by the black lines AA', BR' and CC'. Some of the stars, viz., those
that are situated in the part of the celestial dome represented by
H'PB, will be visible throughout the night, as their circles of revolution
will be above the horizon B'C'D'H. But all the stars, whose Polar
distance is greater than PB or PH, will in their daily revolution, be
partly above and partly below the horizon. For instance, the stars at C
and D will describe circles, some portions of which will be below the
horizon H'H. In other words, the appearance of the visible celestial
hemisphere to a person, whose zenith is at Z, will be different from
the appearance presented by the heavens to an observer at the
North Pole. The stars will not now revolve in horizontal planes, but
obliquely. A great number of them would be circumpolar and visible
during the whole night, but the remaining will rise and set as with us
in the tropics, moving in oblique circles. When Z is very near P, only a