Spelljammer
Direction Sense
This arcane ability allows the character to determine relative position. If the character makes his skill roll, then he knows where he is relative to where he was previously as he moves. The GM may apply negative modifiers for particularly twisting routes.

When the character is able to see the sky, he has a chance to determine which direction is north. This chance is equal to 15 + ((INT - 15) x 3) + (Rank x 5). This roll will usually be made by the GM. If unable to see the sky, the bonus is cut in half (round up).