Sagittarius constellation
Sagittarius (the Archer) is a constellation in the southern sky, best seen in the evening in August. Its brightest star is Kaus Australis (magnitude 1.85). It contains the Teapot. Sagittarius covers 867 square degrees and is the 15th-largest of the 88 constellations.
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How to find Sagittarius, step by step
The Teapot east of the Scorpion.
- On summer evenings find Scorpius low in the south, with red Antares and the curved tail.
- Just east (left) of the stinger, Shaula, lies a group of eight stars shaped like a teapot: the lid, the spout to the right and the handle to the left.
- Kaus Australis is the bottom of the spout side and the brightest star; Nunki is on the handle. The Milky Way rises like steam from the spout: the center of our galaxy lies in that direction.
Detailed star map of Sagittarius
Facts
| Latin name | Sagittarius (genitive: Sagittarii) |
|---|---|
| Abbreviation | Sgr |
| Meaning | the Archer |
| Area | 867 square degrees (15th of 88) |
| Location | right ascension 19.2 h, declination −28° |
| Visible from | latitudes 45° N to 90° S (whole constellation) |
| Best month | August (at about 9 pm) |
| Brightest star | Kaus Australis |
| Stars brighter than magnitude 6 | 113 |
| Named stars (IAU) | 13 |
| Messier objects | M8, M17, M18, M20, M21, M22, M23, M24, M25, M28, M54, M55, M69, M70, M75 |
| Neighbors | Aquila, Capricornus, Corona Australis, Microscopium, Ophiuchus, Scorpius, Scutum, Serpens, Telescopium |
How to find Sagittarius
From 40° N (the USA, southern Europe, Japan) look south in August evenings: at about 9 pm Sagittarius stands highest, around 22° above the southern horizon. From 35° S (Australia, South Africa, Argentina) it is highest in the north, about 83° above the horizon. The months before and after (July and September) are also good: then it is up a couple of hours earlier or later.
Sagittarius borders Aquila, Capricornus, Corona Australis, Microscopium, Ophiuchus, Scorpius, Scutum, Serpens and Telescopium.
Asterisms with stars in Sagittarius: Teapot.
Stars of Sagittarius
Sagittarius has 113 stars brighter than magnitude 6, the limit of the naked eye under a dark sky. These are the brightest:
| Star | Designation | Magnitude | Type | Distance |
|---|---|---|---|---|
| Kaus Australis | ε Sagittarii | 1.85 | B9.5III | — |
| Nunki | σ Sagittarii | 2.02 | B2.5V | 228 ly |
| Ascella | ζ Sagittarii | 2.6 | A2III+A4IV | — |
| Kaus Media | δ Sagittarii | 2.7 | K3-IIIa* | 416 ly |
| Kaus Borealis | λ Sagittarii | 2.81 | K1+IIIb | 84 ly |
| Albaldah | π Sagittarii | 2.89 | F2II | 353 ly |
| Alnasl | γ2 Sagittarii | 2.99 | K0III | 106 ly |
| — | η Sagittarii | 3.11 | M3.5III | — |
| — | φ Sagittarii | 3.17 | B8III | — |
| — | τ Sagittarii | 3.32 | K1+IIIb | — |
| — | ξ2 Sagittarii | 3.51 | K1III | — |
| — | ο Sagittarii | 3.77 | G9IIIb | — |
Deep-sky objects in Sagittarius
Sagittarius contains 15 objects from Charles Messier's catalog:
- Lagoon Nebula (M8): emission nebula, 6.0 mag
- Omega Nebula (M17): emission nebula, 6.0 mag
- Messier 18 (M18): open cluster, 6.9 mag
- Trifid Nebula (M20): emission nebula, 6.3 mag
- Messier 21 (M21): open cluster, 5.9 mag
- Messier 22 (M22): globular cluster, 6.2 mag
- Messier 23 (M23): open cluster, 5.5 mag
- Sagittarius Star Cloud (M24): star cloud, 4.6 mag
- Messier 25 (M25): open cluster, 4.6 mag
- Messier 28 (M28): globular cluster, 5.7 mag
- Messier 54 (M54): globular cluster, 7.6 mag
- Messier 55 (M55): globular cluster, 6.5 mag
- Messier 69 (M69): globular cluster, 8.3 mag
- Messier 70 (M70): globular cluster, 9.1 mag
- Messier 75 (M75): globular cluster, 8.3 mag
Printable Sagittarius map and outline
A black and white version for printing and a plain outline of the Sagittarius figure, useful for school projects, worksheets and learning to recognize the shape.
History
Sagittarius is one of the 48 constellations listed by Ptolemy in the Almagest (2nd century AD). Its official boundary was drawn by Eugène Delporte for the International Astronomical Union in 1930.
Questions about Sagittarius
What is the brightest star in Sagittarius?
Kaus Australis, at magnitude 1.85.
When can you see Sagittarius?
Sagittarius is best seen in the evening in August. The whole constellation is visible from latitudes between 45° N and 90° S.
How many stars are in Sagittarius?
113 stars in Sagittarius are brighter than magnitude 6 and can be seen with the naked eye under a dark sky; 13 of them have official IAU names.
What does Sagittarius mean?
Sagittarius means “the Archer” in Latin. Its abbreviation is Sgr and the genitive, used in star names such as ε Sagittarii, is Sagittarii.
