Question 1616Navigation General

The correct answer is A) in lower transit. When the Sun's center is in lower transit, it is coincident with the principal vertical circle, which is the vertical circle that passes through the north and south points of the horizon. This occurs when the Sun crosses the local meridian, which is the north-south line that passes through the observer's location. At this point, the Sun's azimuth is exactly due south (180 degrees), and its altitude is at its maximum for the day. The other answer choices are incorrect because they do not describe a scenario where the Sun's center is coincident with the principal vertical circle. Option B is incorrect because the hour circle and prime vertical are not necessarily coincident. Options C and D are incorrect because the Sun's azimuth is not exactly 135 degrees east or west when its declination is zero degrees.