By default, the map is drawn with south at the bottom. You can change this by right-clicking on the star map to bring up the view menu:
Selecting
east for example will redraw the map with the eastern horizon at the
bottom - the view you would get if you turned to face towards the east. A
'compass' at the top right of the map reminds you of the map's new orientation:
The compass arrow always points to the northern point on the horizon and in this example, of course, it shows the 'E' - for east - at the bottom.