罗睺、计都天文含义考源

A VERIFICATION TO RAHU AND KETU

罗 、计都是与推步交食有关的两颗隐曜，最早随佛教特别是密教经典传入中国，并逐渐被纳入中国古代天文历算体系中，但历代学者对罗、计都的天文含义理解各不相同。本文通过对较早传入的密教经典《七曜攘灾诀》中罗、计都历表的分析，并结合现代月球运动理论推算，考定罗、计都的天文本义为：罗为白道升交点；计都为白道远地点。

Rahu and Ketu were two invisible celestial body according to the Buddhist Scriptures which were introduced into China during Tang Dynasty.Many scholars believed that Rahu is the ascending node and Ketu is the descending node of lunar orbit,or,on the contrary,Rahu,the descending node;Ketu,the ascending node.However,after careful interpretation and calculation to the Ephemerides of Rahu and Ketu in the Buddhist Scripture──‘Ch’iyao Jang-tsai-chueh',we found that Rahu is the lunar ascending node,but Ketu is the lunar apogee.The Paper also discusses the origin of Rahu and Ketu.