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單項選擇題

In the horizon system of coordinates what is equivalent to the equator on the Earth?（）.

A.Prime vertical circle
B.Principal vertical circle
C.Parallels of altitude
D.Horizon

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單項選擇題

In order for a star to be used for a sight at lower transit，the star must（）.

A.be circumpolar
B.have a declination equal to or greater than your latitude
C.have a GHA of 180°
D.have the SHA equal to or less than the LHA

單項選擇題

In low latitudes，a first quarter Moon will always rise at about（）.

A.sunrise
B.1200 LMT
C.sunset
D.2400 LMT