What is the name of the angle between the horizon and the polar axis?

• A. Latitude
• B. Altitude
• C. Declination
• D. Co-altitude

Answer: (A)

The angle between the horizon and the polar axis equals your latitude. The polar axis points toward the celestial pole, and the altitude of that pole above the horizon at your location is exactly how far north or south you are. At the equator the pole is on the horizon (zero degrees), and at higher latitudes it rises higher, up to 90 degrees at the North Pole. Altitude is about how high a specific object is above the horizon, not the pole itself. Declination is a coordinate on the celestial sphere, not a measure from your horizon to the pole. Co-altitude isn’t the standard term used here. So the described angle is your latitude.