Messier objects of Scorpius, Sagittarius and Ophiuchus

Looking towards Sagittarius, we look towards the centre of our Galaxy, 26 000 light-years away behind clouds of dust. The Milky Way here is at its brightest, and binoculars swept along it from the tail of Scorpius to the top of the Teapot find a cluster or a nebula in almost every field. Thirty of the 110 Messier objects lie in this region, most of them globular clusters, which gather round the centre of the Galaxy, and open clusters and nebulae, which lie in its disc. In this section we find each of them from the stars of Section O1.4.

O1.10.1Scorpius

Scorpius holds four Messier objects, and two more lie just east of it. M4, at a distance of about 7000 light-years, is one of the nearest globular clusters, and it lies 1.3° west of Antares. The globular cluster M80 is small and bright, and lies at the midpoint of the line from Antares to Acrab (β Sco), within 0.1° of it. At the other end of the constellation, beyond the curl of the tail, are two bright open clusters. M6, the Butterfly Cluster, lies 5.0° north of Shaula, the brightest star of the sting, and M7, Ptolemy's Cluster, 4.7° north-east of Shaula, is visible to the naked eye as a hazy patch larger than the full Moon. East of Antares, in the part of Ophiuchus that reaches down between Scorpius and Sagittarius, lie two more globular clusters, M19 7.4° east of Antares and M62 7.9° south-east of it.

O1.10.2The Teapot of Sagittarius

Eight of the brightest stars of Sagittarius make the Teapot, and Sagittarius holds fifteen Messier objects, more than any other constellation. Above the spout, 6.1° north of Alnasl (γ Sgr), lies the Lagoon Nebula, M8, a glowing cloud of hydrogen visible to the naked eye under a dark sky. The Trifid Nebula, M20, lies 1.4° north of it, and the open cluster M21 0.6° north-east of M20. Above the lid, the globular cluster M22, the brightest of Sagittarius, is 2.4° north-east of Kaus Borealis (λ Sgr), and the smaller M28 1.0° north-west of Kaus Borealis. Along the base of the Teapot lie three faint globular clusters, M69 2.5° north-east of Kaus Australis (ε Sgr), M70 a little east of the middle of the line from M69 to M54, and M54 1.7° west of Ascella (ζ Sgr). M54 is far more distant than the others, at about 87 000 light-years, because it belongs to a small galaxy being pulled apart by our own. Further east lie M55, 8.1° east of Ascella, and M75, 8.0° south-west of Dabih (β Cap).

A line drawn north from Kaus Borealis, through the brightest part of the Milky Way, passes four objects in turn. The Sagittarius Star Cloud, M24, a patch of the Milky Way itself, is 7.4° north. Then come the open cluster M18 at 8.5°, the Omega Nebula, M17, at 9.4°, and the Eagle Nebula, M16, at 11.8°, in Serpens, all within 1.3° of the same line. The open clusters M25 and M23 lie 6.4° north and 9.6° north-west of Kaus Borealis.

O1.10.3Ophiuchus, Serpens and Scutum

Ophiuchus is large and faint, and its seven Messier objects, all globular clusters, are found from its few bright stars. M10 and M12 lie 3.3° apart near the middle of the constellation, 10.7° and 8.4° east of Yed Prior (δ Oph). M14 is 7.9° south of Cebalrai (β Oph), M9 3.5° south-east of Sabik (η Oph), and M107 2.7° south-west of ζ Oph. With M19 and M62 in the south, Ophiuchus holds seven globular clusters in all, as many as Sagittarius and more than any other constellation. In Serpens Caput, the head of the Serpent, the large globular cluster M5 lies 7.7° south-west of Unukalhai (α Ser).

Scutum, the Shield, is a small constellation between Aquila and Sagittarius whose stars are all fainter than magnitude 3.8. It holds the open cluster M11, the Wild Duck Cluster, one of the richest open clusters in the sky, 4.0° west of λ Aql, and the smaller M26 3.4° south-west of M11.

All 30 Messier objects of the section are listed below with their way from the nearest bright star.