Q&A: General Astronomy and Space Science

Q:
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?

A:
The Chandra sky map, as shown at

http://chandra.harvard.edu/photo/map/

shows the positions of objects in the galactic coordinate system. A nice explanation of this coordinate system is given at:

http://chandra.harvard.edu/xray_astro/navigation.html

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.