单项选择题
A sidereal day is approximately how much shorter than a solar day?（）
A.4 minutes
B.8 minutes
C.12 minutes
D.16 minutes
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相关考题
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单项选择题
A sextant having an index error that is off the arc has a（）.
A.positive correction
B.dip error
C.negative correction
D.semidiameter error -
单项选择题
A semidiameter correction is applied to observations of（）.
A.Mars
B.the Moon
C.Jupiter
D.All of the above -
单项选择题
A phase correction may be applicable to correct the sextant altitude correction of（）.
A.any star
B.the Sun
C.third magnitude stars only
D.some planets
