A Sextant is a tool and /or piece of equipment craftable using Tinkering (at level 3) from an ingot and pack of nails as well as purchaseable at certain Shops, such as the Tinkering shop for 20 g p, in many hamlets, villages, towns, even the cities.
If functions similarly to an Orb of Seeing, made from enchanting, except instead of being in relative-terms of the position of another player whose Character name is entered, a sextant gives an absolute position. "N" is North, and the far NW corner of the overall surface-based Oberin Map is "0 N, 0 E," while E is East. This by the way is close to the Ice Dungeon.
Because it gives an absolute position, it is invaluable for finding places amid a sea of green or expanse of blue, of significance, but not shown on the Map, such as another character one cannot Orb (q.-Chars or qChar), or else "Corpse of so-and-so," as when one has tapped the Sextant (no name needed) recently, even one's own; if another sextant is found, since (and less than the 45 min. poof limit).
viGilante constructed a Sextant-based Map of all Public Temples, Stables and Guild Halls, including the first two types of information on the latter, which he posted in the Oberin Forum, General as "Noob Node non-Ghost Mapping Project."