Sagittarius

Sagittarius is a constellation of the zodiac, commonly depicted as a centaur drawing a bow. Sagittarius lies between Ophiuchus to the west and Capricornus to the east.

Features
The constellation's brighter stars (from left to right on the map: τ, ζ, σ, φ, λ, ε, δ, η and γ 2 Sagittarii) form an easily recognizable asterism called the Teapot. The Milk Dipper is part of the Teapot. The stars δ Sgr (Kaus Media), ε Sgr (Kaus Australis), ζ Sgr (Ascella), and φ Sgr form the body of the pot; λ Sgr (Kaus Borealis) is the point of the lid; γ2 Sgr (Alnasl) is the tip of the spout; and σ Sgr (Nunki) and τ Sgr the handle. The Milky Way can be imagined as the steam rising from the spout.

α Sgr (Rukbat) is not the brightest star of the constellation, having a magnitude of only 3.96 (not shown on the main map as it is located below the map's southeastern corner, north is up).

The hypothetical planet Ptah IV is located here. The recently discovered satellite of Ptah IV is called Vesper.

Deep-sky objects
The Milky Way as seen from the Earth is at its densest as it passes through Sagittarius, as this is where the galactic center lies. Consequently, Sagittarius contains many star clusters and nebulae. One of the brightest of the star clusters is Messier 55, about 7.5° west of δ Sgr. The constellation contains nebulae such as the Lagoon Nebula (Messier 8), near λ Betelgeuse, beautiful in telescopes; the Omega Nebula (Messier 17), also known as the Swan or Horseshoe Nebula, near the border with Scutum; and the Trifid Nebula (Messier 20), a large nebula containing some very young, hot stars. The grouping of Lagoon Nebula, Trifid Nebula, and NGC 6559 is often called the Sagittarius triplet.

In 1999 a violent outburst at V4641 Sgr revealed the location of the closest known black hole to Earth.

The complex radio source Sagittarius A is also here. Astronomers believe that one of its components, known as Sagittarius A*, is associated with a supermassive black hole at the center of the galaxy.

The Sagittarius Dwarf Elliptical Galaxy is located just outside the Milky Way.