《汉书·传·楚元王传》
从建始以来，二十年间八次食，大概两年零六个月发生一次，古今少有。
自建始以来，二十岁间而八食，率二岁六月而一发，古今罕有。
Since the inception of the Jian Dynasty, there have been eight eclipses in 20 years, roughly one occurring every 2 years and six months, a rare occurrence in ancient and modern times.