Where are we? Where is someplace else? And how do I get there from here? These are questions we need to answer both on the Earth and in the sky to assign a location to a place or celestial object on the surface of a sphere. This lecture includes a review of angular units and the terrestrial system of latitude and longitude on the spherical Earth. We then define the Celestial Sphere, with its Celestial Equator and Poles, and begin to define an analogous coordinate system on the sky. An important wrinkle is that what part of the sky we see at any given time depends on both where we are on the Earth, and what date/time it is. This gives us the elements of the coordinate system we will need to begin our exploration of motions in the sky in the next lectures. Recorded 2007 Sep 25 in 1000 McPherson Lab on the Columbus campus of The Ohio State University.