单项选择题
A.as the basis for star charts B.to enter a star finder C.in sight reduction using Pub 249 D.in sight reductions of planet observations
Right ascension is primarily used by the navigator for（...
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
Planetary aberration is due，in part，to（）.A.refraction o...
单项选择题Planetary aberration is due，in part，to（）.
A.refraction of light as it enters the Earth's atmosphere B.rotation of the Earth on it's axis C.the body's orbital motion during the time required for its light to reach Earth D.a false horizon
Perihelion is the point where the Sun（）.A.is nearest to...
单项选择题Perihelion is the point where the Sun（）.
A.is nearest to the Earth B.is farthest from the Earth C.is on the opposite side of the Earth from the Moon D.and Moon and Earth are in line
