单项选择题
Right ascension is primarily used by the navigator for().
A.calculating amplitudes B.calculating great circle sailings by the Agiton method C.entering the Air Navigation Tables (Selected Stars) Pub 249 D.plotting on star finders
单项选择题 Planetary aberration is due,in part,to().
单项选择题 Perihelion is the point where the Sun().
单项选择题 Other than the Sun and Moon,the brightest object in the sky is().