Sagittarius

scorpius

Abbreviation: Â Sgr
English Name: Â The Archer
Genitive:Â Rukbat
Hemisphere:  Southern Hemisphere (Parts visible from the UK.)
Location:Â Between the constellations of Capricornus and Scorpius.
Visible between latitudes: Â +55 and -90 degrees
Best season: Summer
Seen in three seasons:Â Autumn, Summer, and Winter.
Best seen in:  August
Seen between:Â Late July/August.
Right Ascension (RA):  19 hour
Declination (DEC):Â Â +25 degrees
Area (square degrees): Â 867 (14th)

Sagittarius  (The Archer)

  • Most of Sagittarius, forms an asterism known as The Teapot, lies in the Milky-Way, only a small part on the east lying well away from the galactic plane.
  • The galactic center lies just with the constellation of Sagittarius at the far southwestern corner close to the area known as Baade’s Window.
  • Sagittarius contains 11 Messier objects, many planetary nebulae, most are faint and difficult to detect – only one galaxy (NGC 6822), on the borders of the Milk-Way.
  • Our Sun passes through Sagittarius from 18th December to 19th January – including the Winter Solstice - in wintertime, our Sun appears at noon at its lowest altitude above the horizon. (See diagram.)

Messier Objects

  • M8 Â – Â Gasesous Nebula; also known as the Lagoon Nebula, bright nebula is visible to the naked-eye and a good target for binocular and telescopes reveal a dark lane against the glowing background with one half containing Open Cluster (NGC 6530).
  • M17 Â – Â Gaseous Nebula; visible in binoculars show Open Cluster (NGC 6618) within a gaseous cloud, a telescope required to reveal its better details – more wealth of details on large telescopes. Also known as The Omega Nebula or The Swan Nebula. Â (I prefer it’s the Swan Nebula, because of showing its shape as the swan.)
  • M20 Â – Â Gaseous Nebula; also known as The Trifid Nebula, although detectable with binoculars- requires a telescope for the detailed structure to be seen.
  • M22 Â – Â Globular Cluster; very bright that is actually visible to the naked-eye under good conditions and easy to find with binocular; the third brightest globular cluster in the sky.
  • M23 Â – Â Open Cluster; rich elongated in shape, and almost the same size as Full Moon.
  • M24 Â – Â Star Clouds; an excellent sight through binocular looking at “Small Sagittarius Star Clouds” – a patch of the Milky-Way that is extremely rich in stars, there is a small open cluster (NGC 6603) within it, but this was not what messier described.
  • M25 Â – Â Open Cluster; visible to the naked-eye and a good objects for observation with binoculars or a small telescope.
  • M54  –  Globular Cluster; perhaps the most distant globular – easily found in the sky, being close to the star ζ Sagittarii, however, not resolvable into individual stars even with larger telescopes.
  • M55 Â – Â Globular Cluster; brighter – clearly resolved with even 3-inch telescope; close globular cluster.
  • M69 Â – Â Globular Cluster; slightly elliptical and relatively compact. Readily visible with 3-inch telescope and clearly resolved with 6-inch telescope.
  • M70 Â – Â Globular Cluster; small but bright (magnitude: +7.8), visible as a hazy spot with 3-inch telescope.

Features of Interest

  • NGC 6520 Â – Â Open Cluster; magnitude +7.6, there is an orange star near the centre – clearly visible and high irregular dark nebula (Barnard 86), the dark cloud is readily visible with a small telescope.
  • NGC 6522 Â – Â Globular Cluster; small, but fairly bright, begins to be resolved with 10-inch telescope.
  • NGC 6544 Â – Â Globular Cluster; highly concentrated in a fine field – requires telescope more than 4-inch to be resolved.
  • NGC 6818 Â – Â Planetary Nebula; Magnitude: +9.9, clearly visible with just 3-inch telescope. It s large bluish in tint and elliptical shape.
  • NGC 6822 Â – Â Barnard’s Galaxy; irregular galaxy – difficult object, only faintly seen with 8-inch telescope,although glimpsed with smaller telescopes on exceptionally clear nights.

Named Stars

  • Rukbat (Alpha Sgr)
  • Arkab Prior (Beta 1 Sgr)
  • Arkab Posterior (Beta 2 Sgr)
  • Nash (Gamma 2 Sgr)
  • Kaus Meridionalis (Delta Sgr)
  • Kaus Australis (Epsilon Sgr)
  • Ascella (Zeta Sgr)
  • Kaus Borealis (Lambda Sgr)
  • Ain al Rami (Nu 1 Sgr)
  • Albaldah (Pi Sgr)
  • Nunki (Sigma Sgr)
  • Terebellum (Omega Sgr)
  • Terebellum (59 Sgr)
  • Terebellum (60 Sgr)
  • Terebellum (62 Sgr)

Others

  • Photo of the constellation;Â Sagittarius, as it appears to the naked eye. (Lines have been added for clarity)
  • Sky Chart  –  Sagittarius
  • List of stars in Sagittarius

Back to The 88 Constellations Lists  page.

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