SkyEye: Sagittarius

The Archer

Abbreviation:	Sgr
Genitive:	Sagittarii
Origin:	[antiquity]
Fully Visible:	90°S – 45°N

Sagittarius is a member of the zodiac. This is one of the most ancient of constellations, harking back to Babylonia where it represented the god Nerigal or Nergal, a centaur-like creature with a bow and arrow. The Greeks also associated this constellation with a centaur armed with a bow. It may represent Chiron, esteemed tutor to many a Greek hero. The southern hemisphere also has a centaur constellation.

The asterism of the 'Teapot' is composed of the stars λ Sgr, φ Sgr, σ Sgr, τ Sgr, ζ Sgr, ε Sgr, γ Sgr and δ Sgr. The accompanying 'Teaspoon' is outlined by ξ² Sgr, ο Sgr, π Sgr and ρ¹ Sgr.

The constellation of Sagittarius

Notable Features

Visible Named Stars
α Sgr	Rukbat	This star sometimes appears as Al Rami (from the Arabic al‑rāmī meaning 'the archer') in older star atlases and catalogues.
β¹ Sgr	Arkab Prior	Despite their closeness in the sky, β¹ Sgr and β² Sgr are unrelated star systems.
β² Sgr	Arkab Posterior	The word 'arkab' is derived from the Arabic term meaning 'the hamstring' or 'Achilles tendon'. These two star systems are located in the lower leg of the figure of the centaur.
γ² Sgr	Alnasl	This star sometimes appears as Nash or Nushaba (from the Arabic zujji n‑nushshābah meaning 'the arrowhead') in older star atlases and catalogues. This star also appears as Aoul al Waridah (from the Arabic awwal al‑naʿām al‑wārid meaning 'the first drinking ostrich') in Mohammad Al Achsasi Al Mouakket's calendarium.
δ Sgr	Kaus Media	This star appears as Thanih al Waridah (from the Arabic al‑thānī al‑naʿām al‑wārid meaning 'the second drinking ostrich') in Mohammad Al Achsasi Al Mouakket's calendarium. In Hindu astronomy, δ Sgr and ε Sgr together are known as Purva Ashadha, from the Sanskrit pūrva āṣāḍhā meaning 'the first of the āṣāḍhā'.
ε Sgr	Kaus Australis	This star appears as Thalath al Waridah (from the Arabic al‑thālitha al‑naʿām al‑wārid meaning 'the third drinking ostrich') in Mohammad Al Achsasi Al Mouakket's calendarium.
ζ Sgr	Ascella	This star appears as Thalath al Sadirah (from the Arabic al‑thālitha al‑naʿām al‑ṣādira meaning 'the third returning ostrich') in Mohammad Al Achsasi Al Mouakket's calendarium. In Hindu astronomy, ζ Sgr and σ Sgr together are known as Uttara Ashadha, from the Sanskrit uttara āṣāḍhā meaning 'the second of the āṣāḍhā'.
λ Sgr	Kaus Borealis	This star sometimes appears as Rai al Naaim (from the Arabic rāʿi al‑naʿām meaning 'the keeper of the ostriches') in older star atlases and catalogues.
ν¹ Sgr	Ainalrami	The name only applies to the primary or brightest member of this triple star system.
μ Sgr	Polis	This star sometimes appears as Alnam (from the Arabic al‑naʿāʾim meaning 'the ostriches') in older star atlases and catalogues.
π Sgr	Albaldah	This multiple star system has a combined magnitude of +3.
σ Sgr	Nunki	This star appears as Thanih al Sadirah (from the Arabic al‑thānī al‑naʿām al‑ṣādira meaning 'the second returning ostrich') in Mohammad Al Achsasi Al Mouakket's calendarium.
ω Sgr	Terebellum	This star, together with the stars 59 Sgr, 60 Sgr, and 62 Sgr, form an asterism known to Ptolemy as the Terebellum.
HD 179949	Gumala	This sixth-magnitude star is known to have at least one exoplanet.
Other Interesting Stars
V1216 Sgr		This variable star is less than 10 light years away but is still too dim to be seen with the naked eye.
HD 164604	Pincoya	This tenth-magnitude star is known to have at least one exoplanet and is located just north of γ⊃1 Sgr.
HD 181342	Belel	This eighth-magnitude star is known to have at least one exoplanet. It is found in the vinicity of χ¹ Sgr and χ³ Sgr.
HD 181720	Sika	Located south of the asterism of the 'Teapot', this eighth-magnitude star is known to have at least one exoplanet.
Deep Sky Objects
M8	Lagoon Nebula	This giant emission nebula is one of the few faintly visible to the naked eye. Optical aids reveal more detail, including a star cluster.
M17	Horseshoe Nebula, Ω Nebula, Swan Nebula	Binoculars or a telescope are necessary to see this star-forming region, one of the most massive ones so far discovered in our galaxy.
M18		This open star cluster sits in the rich star fields of Sagittarius. Binoculars are required to view it.
M20	Triffid Nebula	A small telescope shows this object to be an unusual combination of open star cluster, emission nebula, reflection nebula and dark nebula.
M21		Even small binoculars will reveal this young open star cluster.
M22		One of the first globular cluster discovered, it is actually one of the brightest such objects in the sky. It is one of the very few globular clusters to possess a planetary nebula.
M23		A medium-size telescope will show this open star cluster lurking in the starfields of the Milky Way.
M24		The Milky Way runs right through this constellation; hence there are many fine clusters and nebula to be seen. M24 is such a star cluster and is sometimes called the Sagitarius Star Cloud. Binoculars can reveal up to 1000 stars.
M25		This is yet another open star cluster.
M28		This globular cluster contains a dozen or more millisecond pulsars. It is faintly visible in binoculars.
M54		Originally thought to belong to our galaxy, this globular cluster most likely belongs to a nearby galaxy called the Sagittarius Dwarf Elliptical Galaxy.
M55		This is another globular cluster visible through binoculars although to resolve it into individual stars, a medium-size telescope will be required.
M69		This metal-rich globular cluster lies near the galactic centre.
M70		This globular cluster lies near its neighbour, M69.
M75		A telescope will reveal this globular cluster with its densely concentrated core of old stars.
C57	Barnard's Galaxy	Barnard's Galaxy (NGC 6822) is a barred irregular galaxy and a member of our own Local Group. It is detectable in a medium-size telescope.
Sgr A*	Galactic Centre	The galactic centre is denoted by the a bright radio source called Sagittarius A* (pronounced Sagittarius A Star). It is thought to be the location of the supermassive black hole at the very centre of our galaxy.