Constellation, Sgr
Sagittarius: the Archer
Sagittarius covers 868 square degrees of sky, the 15th largest of the 88. Its brightest star is Kaus Australis. It is best placed in the evening sky in August.
Show Sagittarius in the live sky
Sagittarius at a glance
| Fact | Value |
|---|---|
| IAU abbreviation | Sgr |
| Meaning | the Archer |
| Pronounced | SAJ-ih-TARE-ee-us |
| Genitive, used in star names | Sagittarii (for example a Bayer name such as α Sagittarii) |
| Area | 868 square degrees, number 15 of 88 by size |
| Stars to magnitude 6 in our catalogue | 117 |
| Brightest star | Kaus Australis, magnitude 1.8 |
| Best seen | Evenings in August, when it is highest at 9 pm |
| Declination range | -45° to -12° |
| Borders | Corona Australis, Capricornus, Microscopium, Aquila, Ophiuchus, Telescopium, Scutum, Scorpius, Serpens, Indus |
Where on Earth you can see Sagittarius
Sagittarius spans declinations -45° to -12°. Every part of it rises above the horizon at some moment for observers between latitudes 90°S and 45°N. Some of it can be seen from latitudes 90°S to 78°N. South of 78°S none of it ever sets. This is geometry only: it ignores haze, hills and buildings near the horizon.
From six cities
| City | Latitude | Visibility | Middle at its highest |
|---|---|---|---|
| Pune | 18.5°N | All of it rises | 44° |
| New York | 40.7°N | All of it rises | 21° |
| London | 51.5°N | Only part of it rises | 11° |
| Tromsø | 69.6°N | Only part of it rises | below the horizon |
| Tokyo | 35.7°N | All of it rises | 26° |
| Sydney | 33.9°S | All of it rises | 84° |
Sagittarius's named stars
These stars in Sagittarius have names approved by the IAU Working Group on Star Names. Magnitude is brightness: a lower number is brighter, and the faintest stars seen with the naked eye on a dark night are about magnitude 6.
| Star | Designation | Magnitude | Distance (light-years) |
|---|---|---|---|
| Kaus Australis | ε Sagittarii | 1.79 | 140 |
| Nunki | σ Sagittarii | 2.05 | 230 |
| Ascella | ζ Sagittarii | 2.60 | 88.2 |
| Kaus Media | δ Sagittarii | 2.72 | 350 |
| Kaus Borealis | λ Sagittarii | 2.82 | 78.2 |
| Albaldah | π Sagittarii | 2.88 | 510 |
| Alnasl | γ2 Sagittarii | 2.98 | 96.9 |
| Polis | μ Sagittarii | 3.84 | not known |
| Arkab Prior | β1 Sagittarii | 3.96 | 310 |
| Rukbat | α Sagittarii | 3.96 | 180 |
| Arkab Posterior | β2 Sagittarii | 4.27 | 130 |
| Terebellum | ω Sagittarii | 4.70 | 84.8 |
| Ainalrami | ν1 Sagittarii | 4.86 | 1,100 |
Distances are about, from the HYG database (Hipparcos parallax), and "not known" means the catalogue has no reliable parallax for that star.
How these facts were found
The name, meaning and boundaries are the IAU's. Area, borders and the latitude ranges are computed from those boundaries; the brightest star and the star count come from a magnitude-6 star catalogue; star names are matched to the catalogue by Hipparcos number and checked by position. The month is when Sagittarius's middle crosses the north-south line of the sky at 9 pm local solar time. See How we know.
Sources
- IAU: The Constellations. Names, meanings, pronunciations and boundaries
- IAU Working Group on Star Names. The official names of stars
- astronomy-engine. The MIT licensed library that does the calculations, run on the page's build machine and in the app
- HYG database v4.4 (astronexus). Distances, spectral types and luminosities, licence CC BY-SA 4.0