If the pointing coordinates are too far from the source coordinates, there is an error message saying something like "no photons will hit the detector". That message could be improved to say "Your pointing looks at, but your source is at XX and thus outside of Chandra's field of view."
If the pointing coordinates are too far from the source coordinates, there is an error message saying something like "no photons will hit the detector". That message could be improved to say "Your pointing looks at, but your source is at XX and thus outside of Chandra's field of view."