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Sagittarius (abbr. Sgr, gen. Sagittarii)





The Archer (actually, a centaur with a bow); a large constellation of the southern hemisphere and ninth of the zodiac. It lies north of Corona Australis, south of Aquila, east of Capricornus and west of Ophiuchus. In the center of the constellation lies the conspicuous asterism known as the Milk Dipper or the Teapot, with a spout (formed by the stars Gamma, Delta, and Epsilon Sag), a handle (Zeta, Sigma, Tau, and Phi Sag), and a lid (Lambda Sag). Rich in star fields, star clusters, and nebulae, Sagittarius straddles the plane of the Milky Way. At its very edge, at the border with Ophiuchus and Scorpius, lies the center of the Milky Way Galaxy, about 30,000 light-years distant. See below for details of the constellation's brightest stars and interesting deep sky objects.


Sagittarius constellation
Sagittarius. © 2003 Torsten Bronger.
Copied here under the terms of the GNU Free Documentation License



Stars brighter than magnitude 4.0
Star Visual
mag.
Abs.
mag.
Spectral
type
Distance
(lt-yr)
R.A. (h m s) Dec. ( ° ' '' )
Epsilon (Kaus Australis) 1.79 -1.45 B9.5III 145 18 24 10 -34 23 05
Sigma (Nunki) 2.05 -2.14 B2.5V 224 18 55 16 -26 17 48
Zeta (Ascella) 2.60 0.41 A2III+A4IV 89 19 02 37 -29 52 49
Delta (Kaus Media) 2.72 -2.14 K3IIIa 306 18 21 00 -29 49 42
Lambda (Kaus Borealis) 2.82 0.94 K1IIIb 77 18 27 58 -25 25 18
Pi (Albaldah) 2.82 -2.77 F2II 440 19 09 46 -21 01 25
Gamma (Alnasl) 2.98 0.63 K0III 96 18 05 48 -30 25 26
Eta 3.10 -0.20 M2III 149 18 17 38 -36 45 42
Phi 3.17 -1.08 B8III 231 18 45 39 -26 59 27
Tau 3.32 0.48 K1III 120 19 06 56 -27 40 13
Xi-2 3.52 -1.77 G8II 372 18 57 44 -21 06 24
Omicron 3.76 0.61 K0III 139 19 04 41 -21 44 30
Mu (Polis) 3.84v -8.15 BIape 8,150 18 13 46 -21 03 32
Rho-1 3.92 1.06 F0III 122 19 21 40 -17 50 50
Beta-1 (Arkab Prior) 3.96 -1.37 B9V 378 19 22 38 -44 27 32
Alpha (Rukbat) 3.96 0.37 B8v 170 19 23 53 -40 36 58


Other objects of interest
Name Type of Object Notes
W Sgr star A Cepheid variable. Magnitude range 4.4 to 5.0; period 7d 14h; R.A. 18h 5.0m, Dec. -29° 35'
NGC 6818 planetary nebula Irregular oval shape. Magnitude 10; diameter 0.3'; R.A. 19° 44'
Lagoon Nebula diffuse nebula M8. See separate entry
Omega Nebula diffuse nebula M17. See separate entry
Trifid Nebula diffuse nebula M20. See separate entry
M18 (NGC 6613) open cluster A loose scattering of about 20 stars over 0.2° best viewed with binoculars or a small telescope. Magnitude 6.9; diameter 9'; R.A. 18h 19.0m, Dec. -17° 8'
M21 (NGC 6531) open cluster Easy to resolve with a tight central grouping. Magnitude 6.9; diameter 9'; R.A. 18h 19.0m, Dec. -17° 8'
M23 (NGC 6494) open cluster A large cluster spanning nearly 0.5o, excellent with binoculars and resolvable with a small telescope into about 100 stars. Magnitude 5.5; diameter 27'; R.A. 17h 56.8m, Dec. -19° 1'
M25 (IC 14725) open cluster About 50 stars, the brightest of sixth magnitude; good binocular object. Magnitude 4.6; diameter 31'; R.A. 18h 31.6m, Dec. -19° 15'
NGC 6530 open cluster About 25 stars near the Lagoon Nebula, the brightest of seventh magnitude; another good binocular cluster. Magnitude 4.6; diameter 14'; R.A. 18h 4.8m, Dec. -24° 20'
M24 star field The Sagittarius Star Cloud, part of Milky Way. To naked eye, it appears as a foggy patch; large telescopes reveal a rich field of stars. Magnitude 4.6; diameter 90'; R.A. 18h 16.9m, Dec. -18° 29'
M28 (NGC 6626) globular cluster Magnitude 6.9; diameter 11.0'; R.A. 18h 24.5m, Dec. -24° 52'
M54 (NGC 6715) globular cluster Close to Zeta Sgr and lying within the Sagittarius Dwarf Elliptical Galaxy, it is so dense that it is can mistaken through binoculars for a star. Magnitude 7.7; diameter 9.1'; R.A. 18h 55.1m, Dec. -30° 29'
M55 (NGC 6809) globular cluster A large but loose globular that can be viewed with binoculars. Magnitude 6.9; diameter 19.0'; R.A. 19h 19.0m, Dec. -17° 8'
M69 (NGC 6637) globular cluster Magnitude 7.7; diameter 7.1'; R.A. 18h 31.4m, Dec. -32° 21'
M70 (NGC 6681) globular cluster Magnitude 8.1; diameter 7.8'; R.A. 18h 43.2m, Dec. -32° 18'
M75 (NGC 6864) globular cluster Magnitude 8.6; diameter 6.0'; R.A. 20h 06.1m, Dec. -21° 55'
Sagittarius Dwarf Elliptical Galaxy galaxy See separate entry
Sagittarius A galaxy See separate entry


Constellations
Andromeda | Antlia | Apus | Aquarius | Aquila | Ara | Aries | Auriga | Bootes | Caelum | Camelopardalis | Cancer | Canes Venatici | Canis Major | Canis Minor | Capricornus | Carina | Cassiopeia | Centaurus | Cepheus | Cetus | Chamaeleon | Circinus | Columba | Coma Berenices | Corona Austrina | Corona Borealis | Corvus | Crater | Crux | Cygnus | Delphinus | Dorado | Draco | Equuleus | Eridanus | Fornax | Gemini | Grus | Hercules | Horologium | Hydra | Hydrus | Indus | Lacerta | Leo | Leo Minor | Lepus | Libra | Lupus | Lynx | Lyra | Mensa | Microscopium | Monoceros | Musca | Norma | Octans | Ophiuchus | Orion | Pavo | Pegasus | Perseus | Phoenix | Pictor | Pisces | Piscis Austrinus | Puppis | Pyxis | Reticulum | Sagitta | Sagittarius | Scorpius | Sculptor | Scutum | Serpens | Sextans | Taurus | Telescopium | Triangulum | Triangulum Australe | Tucana | Ursa Major | Ursa Minor | Vela | Virgo | Volans | Vulpecula


Related categories

   • NOTABLE STARS
   • NEBULAE AND STAR CLUSTERS
   • GALAXIES