默认题库 - 天文航海

A. the equator to the elevated pole
B. your horizon to your zenith
C. your zenith to the elevated pole
D. the geographical position of the Sun to the elevated pole

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单选题

Sidereal time is NOT used（）.

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 observatio

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单选题

The approximate positions of the stars are based on sidereal time，which is based upon rotation of the Earth relative to（）.

A. winter solstice
B. autumnal equinox
C. summer solstice
D. vernal equinox

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单选题

Because the actual center of some planets may differ from the observed center，the navigator applies a correction known as the（）.

A. phase correction
B. refraction correction
C. semidiameter correction
D. augmentation correctio

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单选题

A large group of stars revolving around a center is known as a（）.

A. cluster
B. shower
C. constellation
D. galaxy

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单选题

A marine sextant has the index arm set at zero and the reflected image of the horizon forms a continuous line with the actual image. When the sextant is rotated about the line of sight the images separate. The sextant has（）.

A. error of perpendicularity
B. side error
C. prismatic error
D. centering error

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