Term: sky map

SC001 and SC002 map the celestial sphere, but they don't tell us what part of the celestial sphere can be seen at a particular time at a particular location. (That's a plus: these maps can be sold anywhere, and if you can find one star both in the sky and on the maps, you should be able to map the rest of the sky as the relative position of the stars is well presented by the SC maps.) The sky map is a stereographic projection of the hemisphere of the sky onto a circular map. Zenith is at the center of the map; the edges are where the sky ends: the horizon. Just as with SC001 east and west seem reversed because this map is intended to be looked up at rather than down at. Such maps vary both with location and time...they can not be printed up and sold bulk. One nice way to get such a map is from Your Sky (John Walker, Fourmilab). You'll need to tell them your location and the day and time for the map. Remember the stars in the sky are on the move!

The below diagram shows how we could make a stereographic projection of the sky.

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