Sagittarius

scorpius

Abbreviation:  Sgr
English Name:  The Archer
Genitive: Rukbat
Hemisphere:  Southern Hemisphere (Parts visible from the UK.)
Location: Between the constellations of Capricornus and Scorpius.
Visible between latitudes:  
+55 and -90 degrees
Best season: Summer
Seen in three seasons: Autumn, Summer, and Winter.
Best seen in:  August
Seen between: Late July/August.
Right Ascension (RA):  19 hour
Declination (DEC):  +25 degrees
Area (square degrees):  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  –  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  –  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.  (I prefer it’s the Swan Nebula, because of showing its shape as the swan.)
  • M20  –  Gaseous Nebula; also known as The Trifid Nebula, although detectable with binoculars- requires a telescope for the detailed structure to be seen.
  • M22  –  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  –  Open Cluster; rich elongated in shape, and almost the same size as Full Moon.
  • M24  –  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  –  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  –  Globular Cluster; brighter – clearly resolved with even 3-inch telescope; close globular cluster.
  • M69  –  Globular Cluster; slightly elliptical and relatively compact. Readily visible with 3-inch telescope and clearly resolved with 6-inch telescope.
  • M70  –  Globular Cluster; small but bright (magnitude: +7.8), visible as a hazy spot with 3-inch telescope.

Features of Interest

  • NGC 6520  –  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  –  Globular Cluster; small, but fairly bright, begins to be resolved with 10-inch telescope.
  • NGC 6544  –  Globular Cluster; highly concentrated in a fine field – requires telescope more than 4-inch to be resolved.
  • NGC 6818  –  Planetary Nebula; Magnitude: +9.9, clearly visible with just 3-inch telescope. It s large bluish in tint and elliptical shape.
  • NGC 6822  –  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; 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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