Astronomy sky diagrams and photos often have a little key to indicate if they're erect views, inverted views or mirror views.

What used to puzzle me is that an erect view is indicated by

 N
E+

when that looks like it should mean a laterally reflected view, as E is on the 'wrong' side.

But then I realised that when you're looking up at the sky (which is the perspective that a sky photo has) you're looking OUT of the map, not INTO it. Consequently E and W are reversed.