Epicycle
01
本轮, 次级圆形轨道
(astronomy) a secondary circular orbit embedded within a primary circular orbit
例子
In his astronomical work the Almagest, Ptolemy used a system of deferents and epicycles to explain the observed motions of planets across the night sky.
在他的天文著作《天文学大成》中，托勒密使用了均轮和本轮的系统来解释夜空中观测到的行星运动。
02
本轮, 次级圆
a small circle whose center moves around the circumference of a larger circle
例子
The motion of a point on an epicycle can be described mathematically by combining the rotations of the smaller circle and the larger circle.
本轮上一点的移动可以通过结合小圆和大圆的旋转来数学描述。
