Gerhana matahari: Perbezaan antara semakan

 

{{Quotation|Matahari adalah seperti api dan bulan seperti air. Api memberikan cahaya dan air memantulkannya. Oleh itu kecerahan bulan ini dihasilkan daripada cahaya matahari, dan kegelapan bulan (pho) adalah disebabkan (cahaya) matahari dihalang (pi). Sisi yang menghadap matahari diterangi sepenuhnya, dan bahagian yang jauh dari itu gelap. Planet (dan juga bulan) mempunyai sifat air dan memantulkan cahaya. Cahaya mencurah-curah dari matahari (tang jih chih chhung kuang) tidak selalu sampai ke bulan kerana halangan (pi) bumi itu sendiri-ini dipanggil 'an-hsü', a '''[[gerhana bulan]]'''. Apabila (kesan yang sama) berlaku dengan planet (kami memanggilnya) pertemuan (hsing wei); apabila bulan melintas merentasi (kuo)(laluan matahari) maka adanya '''gerhana matahari''' (shih).<ref name="needham volume 3 414">Needham, Volume 3, 414.</ref>}}

 

{{Quotation|The Director [of the Astronomical Observatory] asked me about the shapes of the sun and moon; whether they were like balls or (flat) fans. If they were like balls they would surely obstruct (ai) each other when they met. I replied that these celestial bodies were certainly like balls. How do we know this? By the waxing and waning (ying khuei) of the moon. The moon itself gives forth no light, but is like a ball of silver; the light is the light of the sun (reflected). When the brightness is first seen, the sun(-light passes almost) alongside, so the side only is illuminated and looks like a crescent. When the sun gradually gets further away, the light shines slanting, and the moon is full, round like a bullet. If half of a sphere is covered with (white) powder and looked at from the side, the covered part will look like a crescent; if looked at from the front, it will appear round. Thus we know that the celestial bodies are spherical...Since the sun and moon are in conjunction (ho) and in opposition (tui) once a day, why then do they have eclipses only occasionally?' I answered that the ecliptic and the moon's path are like two rings, lying one over the other (hsiang tieh), but distant by a small amount. (If this obliquity did not exist), the sun would be eclipsed whenever the two bodies were in conjunction, and the moon would be eclipsed whenever they were exactly in position. But (in fact) though they may occupy the same degree, the two paths are not (always) near (each other), and so naturally the bodies do not (intrude) upon one another.<ref name="needham volume 3 415 416">Needham, Volume 3, 415–416.</ref>}}