Sometimes you have to remove stars or nebulae from the map, especially
because they collide with other objects. If you've already read how to
change labels, this is very straightforward. You remove sky objects
with `delete' and add them with `add'. Both commands take
a list of objects that is ended with a semicolon ;:
delete LEO 63 HD 97605 ;
add NGC 6992 ;
The `add' command is useful mostly for nebulae, because by
default, PP3 only includes all objects of the Messier catalogue,
but only other objects with a minimal brightness, see Filtering by brightness.