AS101 Lecture Notes - Lecture 4: Eastern Hemisphere, 50Th Parallel North, Dailymotion
Document Summary
An onject"s altitude (above horizon) and direction (along horizon) specifies its location in your sky. Zenith = altitude is 90 degrees; the point directly overhead. Horizon = altitude is 0 degrees; all points 90 degrees away from zenith. Meridian = line passing through zenith and connecting n and s points on horizon. Not always right now, we are not standing on the north pole if we were standing on the north pole, looking up, then the zenith would be the same as the north pole. When we describe the sky, we must specify where on earth we are observing the sky from. We specify our location or earth using latitude and longitude. 0 degrees = equator, 90 degrees = north pole. Imagine the earth as a transparent sphere (actually the because of earth"s rotation, its equator bulges out a little). Through the transparent earth we can see its equatorial plane. The point o is the center of the earth.
