hour angle

hour-angle的词性：
n.Abbr. ha（名词）缩写 ha

1. The angular distance, measured westward along the celestial equator, between the celestial meridian of the observer and the hour circle passing through a celestial body.
相位角：沿天体赤道向西量出的角距，位于观察者所处的子午线与通过天体的子午线之间