单项选择题
A.when the Moon is low in the sky at rising or setting
B.at the new Moon phase
C.when taking Moon sights during daylight
D.when the terminator is nearly vertical
单项选择题 In working out a local apparent noon sight for your latitude，you subtract the Ho from 90°. The 90°represents the angular distance from（）.
单项选择题 In the navigational triangle，the angle at the elevated pole is the（）.
单项选择题 In the horizon system of coordinates what is equivalent to latitude on the Earth?（）.