Question 1540Navigation General

The correct answer is B) Hour circles. In the celestial equator system of coordinates, the equivalent to the meridians of the Earth system of coordinates are the hour circles. Hour circles are great circles that pass through the celestial poles and intersect the celestial equator at right angles, just as meridians intersect the Earth's equator at right angles. The other options are incorrect because: A) Parallels of declination are the equivalent to latitude lines on Earth, not meridians. C) The horizon is a plane, not a coordinate system. D) Vertical circles are great circles that pass through the zenith and nadir, not the celestial poles.