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

46 THE ARCTIC HOME IN THE VEDAS. North Pole, the northern celestial hemisphere will alone be visible spinning round and round over his head, and the southern half, with all the stars in it, will always remain invisible, while the celestial equator, dividing the two, will be his celestial horizon. To such a man the sun going into the northern hemisphere in his annual course will appear as coming up from the south, and he will express the idea by saying that "the sun has risen in the south," howsoever strange the expression may seem to us. After the sun has risen in this way in the south,— and the sun will rise there only once a year,—he will be constantly visible for 6 months, during which time he will attain a height of about 23½° above the horizon, and then begin to lower down until he drops into the south below the horizon. It will be a long and continuous sunshine of 6 months, but, as the celes- tial dome over the head of the observer will complete one revolution in 24 hours, the sun also will make one horizontal circuit round the observer in every 24 hours; and to the observer at the North Pole the completion of one such circuit, whether of the sun or of the stars, will serve as a measure of ordinary days, or periods of 24 hours, during the long sunshine or night of six months. When about 180 such rounds, (the exact number will depend upon the difference in the durations of summer and winter noticed in the last chapter), are completed, the sun will again go down below the horizon, and the stars in the northern hemisphere, which had disappeared in his light, will become visible all at once, and not rise one after the other as with us. The light of the sun had, so to say, eclipsed them, though they were over the head of the observer; but as soon as this obstruction is removed the whole northern starry hemisphere will again appear to spin round the observer for the remaining period of six months. The horizontal motion of the celestial hemisphere, only one long