<P> The Milky Way is at its densest near Sagittarius, as this is where the galactic center lies . As a result, Sagittarius contains many star clusters and nebulae . </P> <P> Sagittarius contains several well - known nebulae, including the Lagoon Nebula (Messier 8), near λ Sagittarii; the Omega Nebula (Messier 17), also known as the Horseshoe Nebula or Swan Nebula, near the border with Scutum; and the Trifid Nebula (Messier 20), a large nebula containing some very young, hot stars . </P> <Ul> <Li> The Lagoon Nebula (M8) is an emission nebula that is located 5,000 light - years from Earth and measures 140 light - years by 60 light - years (1.5 °). Though it appears grey in telescopes to the unaided eye, long - exposure photographs reveal its pink hue, common to emission nebulae . It is fairly bright, with an integrated magnitude of 3.0 . The Lagoon Nebula was discovered independently by John Flamsteed in 1680, Guillaume Le Gentil in 1747, and Charles Messier in 1764 . The central area of the Lagoon Nebula is also known as the Hourglass Nebula, so named for its distinctive shape . The Hourglass Nebula has its shape because of matter propelled by Herschel 36 . The Lagoon Nebula also features three dark nebulae catalogued in Barnard's Catalog . The Lagoon Nebula was instrumental in the discovery of Bok globules, as Bart Bok studied prints of the nebula intensively in 1947 . Approximately 17,000 Bok globules were discovered in the nebula nine years later as a part of the Palomar Sky Survey; studies later showed that Bok's hypothesis that the globules held protostars was correct . </Li> <Li> The Omega Nebula is a fairly bright nebula; it has an integrated magnitude of 6.0 and is 4890 light - years from Earth . It was discovered in 1746 by Philippe Loys de Chésaux; observers since him have differed greatly in how they view the nebula, hence its myriad of names . Most often viewed as a checkmark, it was seen as a swan by George F. Chambers in 1889, a loon by Roy Bishop, and as a curl of smoke by Camille Flammarion . </Li> <Li> The Trifid Nebula (M20, NGC 6514) is an emission nebula in Sagittarius that lies less than two degrees from the Lagoon Nebula . Discovered by French comet - hunter Charles Messier, it is located between 2,000 and 9,000 light - years from Earth and has a diameter of approximately 50 light - years . The outside of the Trifid Nebula is a bluish reflection nebula; the interior is pink with two dark bands that divide it into three areas, sometimes called "lobes". Hydrogen in the nebula is ionized, creating its characteristic color, by a central triple star, which formed in the intersection of the two dark bands . M20 is associated with a cluster that has a magnitude of 6.3 . </Li> <Li> The Red Spider Nebula (NGC 6537) is a planetary nebula located at a distance of about 4000 light - years from Earth . </Li> <Li> NGC 6559 is a star - forming region located at a distance of about 5000 light - years from Earth, in the constellation of Sagittarius, showing both emission (red) and reflection (blue) regions . </Li> </Ul> <Li> The Lagoon Nebula (M8) is an emission nebula that is located 5,000 light - years from Earth and measures 140 light - years by 60 light - years (1.5 °). Though it appears grey in telescopes to the unaided eye, long - exposure photographs reveal its pink hue, common to emission nebulae . It is fairly bright, with an integrated magnitude of 3.0 . The Lagoon Nebula was discovered independently by John Flamsteed in 1680, Guillaume Le Gentil in 1747, and Charles Messier in 1764 . The central area of the Lagoon Nebula is also known as the Hourglass Nebula, so named for its distinctive shape . The Hourglass Nebula has its shape because of matter propelled by Herschel 36 . The Lagoon Nebula also features three dark nebulae catalogued in Barnard's Catalog . The Lagoon Nebula was instrumental in the discovery of Bok globules, as Bart Bok studied prints of the nebula intensively in 1947 . Approximately 17,000 Bok globules were discovered in the nebula nine years later as a part of the Palomar Sky Survey; studies later showed that Bok's hypothesis that the globules held protostars was correct . </Li>

What does sagittarius look like in the sky