Sextant

A sextant is an archaic navigational instrument used aboard naval ships and some aeronautic planes.

Captain Jean-Luc Picard kept a sextant in his quarters aboard the USS Enterprise-D. When Jono lived in the captain's quarters for some time in 2366, Picard made sure that the boy didn't touch the sextant. (TNG: "Suddenly Human")

Benjamin Sisko used a sextant to navigate while aboard the Bajoran lightship he constructed in late 2371. (DS9: "Explorers")

Background

In the deleted scene from Star Trek: Generations, Jean Luc Picard was given a sextant for Christmas from his family in the Nexus. This scene would be included in the special features of the Star Trek: Generations Special Edition DVD.

The script of the Star Trek: Deep Space Nine episode "Rapture" called for various "sextant-like instruments" to be positioned in a scene in the holosuite.