Which constellation is named after an astronomical sextant?

The constellation named after an astronomical sextant is Sextans.

Sextans is named for the sextant, an instrument astronomers use to measure angular distances between celestial objects and the horizon. The constellation’s name specifically honors the astronomical sextant used by Polish astronomer Johannes Hevelius.

Hevelius introduced Sextans in 1687, calling it Sextans Uraniae, or “Urania’s Sextant.” His own instrument was destroyed when a fire consumed his observatory in Gdańsk on 26 September 1679. He named the constellation in memory of that lost tool, linking a personal tragedy to the star map.

Sextans is a faint constellation on the celestial equator, positioned between Leo, Hydra and Crater. It covers roughly 314 square degrees and is visible from much of Earth because of its equatorial location. Its brightest star, Alpha Sextantis, has an apparent magnitude of about 4.49, so the constellation is difficult to pick out from light-polluted skies. A common mix-up is Pyxis, which represents a mariner’s compass, while Octans represents the octant—another navigational instrument, but not the sextant.