This is a key for the ASCII symbols used on the semi-graphical starmap. It will not be helpful for users who rely on screen readers.
O = planet (arranged in a sphere)
o = moon (arranged in a sphere)
# = space station (singly or arranged in a larger formation)
@ = beacon housing
* = star (never actually present in the sector, seen small and in the distance)
~ = freefloating debris
& = debris chunk
% = asteroid
%] = asteroid station
" = artifact or other miscellaneous object
/ = blockade
$ = interdictor
Other symbols are likely to be temporary space stations or starships, whose symbols change based on controlling alliance and class. A key for these is provided underneath the starmap.