That part of the field of view towards which the star appears to move is called the _preceding_ part of the field, the opposite being termed the _following_ part.

The motion for all stars, except those lying in an oval space extending from the zenith to the pole of the heavens, is more or less from right to left (in the inverted field).

Now, if we suppose a star to move along a diameter of the field so as to divide the field into two semicircles, then in all cases in which this motion takes places from right to left, that semicircle which contains the lowest point (apparently) of the field is the _northern_ half, the other is the _southern_ half.

Over the oval space just mentioned the reverse holds.
Thus the field is divided into four quadrants, and these are termed _north following_ (_n.f._) and _south following_ (_s.f._); _north preceding_ (_n.p._), and _south preceding_ (_s.p._).

The student can have no difficulty in interpreting these terms, since he knows which is the following and which the preceding _semicircle_, which the northern and which the southern.