the sextant · pronounced SEKS-tanz. Sextans is an official IAU constellation representing the sextant. It occupies faint equatorial sky south of Leo, where its outline is best understood as a guide to a formally bounded region rather than a physical group of nearby stars. Alpha Sextantis and Gamma Sextantis provide practical anchors, while NGC 3115 gives observers a destination beyond the line figure. The stars only appear together from Earth: they lie at very different distances and move independently through the Galaxy. Its early-modern name reflects the European chart-making period in which southern or previously unfilled sky regions were formalised. Naked-eye recognition depends on latitude, season, darkness and moonlight. This guide therefore separates the official sky area, the traditional picture and the objects that can actually be observed.
About Sextans
Sextans is one of the 88 constellations recognized by the International Astronomical Union. Its standard three-letter abbreviation is Sex, and astronomers use the genitive form Sextantis when naming stars associated with it. The constellation's reference position lies around right ascension 10.5 hours and declination -7 degrees.
Its location places it in the celestial equator. For a typical mid-latitude observer, this part of the celestial sphere is especially well placed during winter evenings. Exact visibility depends on latitude, local horizon, date and time.
History and mythology of Sextans
Origin and naming
Sextans entered the Western constellation record through Hevelius,1687. Its name means the sextant; historical artwork varies and should not be confused with the IAU boundary adopted for positional astronomy.
From figure to official sky region
The IAU standardised constellation names in 1922, and Eugène Delporte published the modern boundaries in 1930. Every coordinate inside that polygon belongs to this constellation, including stars and galaxies unrelated to its traditional stick figure.
Cultural context
The familiar Western figure is one layer of sky history. Star traditions from other cultures may divide faint equatorial sky south of Leo into smaller asterisms, lunar stations or navigational patterns, so apparent overlap is cross-referenced rather than treated as an identical constellation.
How to find Sextans
- Choose an evening when faint equatorial sky south of Leo is well placed and use a planisphere or sky app set to your location and time.
- Begin with the brightest anchor, Alpha Sextantis, then verify the surrounding angles rather than relying on the artwork alone.
- Trace toward Gamma Sextantis; binoculars help separate the genuine stars from background Milky Way fields or light pollution.
- After confirming the pattern, centre NGC 3115. Start at low magnification and increase power only after the target is securely located.
Bright stars in Sextans
Alpha Sextantis
Notable star- Magnitude
- 4.5
- Distance
- 287 ly
Alpha Sextantis is a characteristic stellar landmark used when tracing this constellation; its brightness, colour or multiplicity rewards comparison in binoculars or a telescope.
Gamma Sextantis
Notable star- Magnitude
- 5.1
- Distance
- 262 ly
Gamma Sextantis is a characteristic stellar landmark used when tracing this constellation; its brightness, colour or multiplicity rewards comparison in binoculars or a telescope.
Beta Sextantis
Notable star- Magnitude
- 5.1
- Distance
- 345 ly
Beta Sextantis is a characteristic stellar landmark used when tracing this constellation; its brightness, colour or multiplicity rewards comparison in binoculars or a telescope.
Deep-sky objects in Sextans
NGC 3115
NGC 3115 is one of the most useful observing or imaging targets in this field. Its apparent size and surface brightness make dark skies and an appropriate field of view important.
Sextans A
Sextans A is one of the most useful observing or imaging targets in this field. Its apparent size and surface brightness make dark skies and an appropriate field of view important.
Sextans B
Sextans B is one of the most useful observing or imaging targets in this field. Its apparent size and surface brightness make dark skies and an appropriate field of view important.
Interesting facts about Sextans
- Sextans's name means the sextant. Sextans entered the Western constellation record through Hevelius,1687.
- Alpha Sextantis is listed at magnitude 4.5. Alpha Sextantis is a characteristic stellar landmark used when tracing this constellation; its brightness, colour or multiplicity rewards comparison in binoculars or a telescope.
- NGC 3115 is a Spindle Galaxy. NGC 3115 is one of the most useful observing or imaging targets in this field.
- The IAU standardised constellation names in 1922, and Eugène Delporte published the modern boundaries in 1930.