佛祖歷代通載 1.185

1.185

(3) The disc of the sun is made of fire jewel (sūryakānta). Its diameter is fifty-one yojanas, its circumference is one hundred and fifty-three yojanas, and its thickness is six yojanas and eighteen parts [of a yojana]. On top it has a gold rim, and upon that are gold, silver, lapis lazuli, crystal, and so forth, elegantly forming four corners. The celestial palaces where the sun god and others reside are driven and circulated by the wind. In one day and one night it circles the four great continents. When the sun travels toward the north, the days grow longer; when traveling south, the days grow shorter; when traveling between north and south, day and night are equal. Through the light of its traveling places, cold and heat arise, marking the limits of winter and summer. Traveling north takes six months, and traveling south takes six months; when it reaches the middle course, it is called the turning of the sun and moon. Its complete transit through the circuit of the stars is called one year.