Q&A: General Astronomy and Space Science
Do the all sky maps represent a maximum distance for the surface of a sphere, and does this sphere represent a look at the sphere from a vantage point outside the surface of the sphere?
The Chandra sky map, as shown at
shows the positions of objects in the galactic coordinate system. A nice
explanation of this coordinate system is given at:
No assumptions are made about how far the plotted objects are away from the
Earth. Some objects are billions of light years away, and others less than
a hundred light years away. The sky map just tells us the direction of a
source in the sky.