Messier objects from Hercules to Perseus

The Andromeda Galaxy, M31, is the most distant thing most people can see with the naked eye. Its light left it about 2.5 million years ago, and on a dark autumn night it shows as an elongated glow a little larger than the full Moon. It is one of 23 Messier objects that lie in a wide band of sky from Hercules, high on summer evenings, to Perseus, rising on autumn ones. Most of them are found by a single clean hop, often along the line between two stars. In this section we find each of them from the patterns of Section O1.4 and Section O1.5.

O1.11.1Hercules and Lyra

M13, the Hercules Globular Cluster, holds several hundred thousand stars and is just visible to the naked eye under a dark sky. It lies a third of the way along the western side of the Keystone, from η Her to ζ Her. The second globular cluster of Hercules, M92, is a little smaller and fainter and often overlooked. It lies 6.3° north of π Her, the north-eastern corner of the Keystone.

In Lyra, the Ring Nebula, M57, a planetary nebula, lies between the two stars at the far end of the small parallelogram below Vega, 0.8° from Sheliak (β Lyr) on the way to Sulafat (γ Lyr). The faint globular cluster M56 lies on the line from Albireo, the head of Cygnus, to Sulafat, a little short of halfway.

O1.11.2Cygnus, Vulpecula and Sagitta

Cygnus lies along the Milky Way and holds two open clusters. M29 is a small group 1.8° south of Sadr, the star at the middle of the Northern Cross. M39 is a large, loose cluster 9.2° north-east of Deneb. Below Cygnus, the small constellation Sagitta, the Arrow, points east. The globular cluster M71 lies close to the middle of its shaft, halfway from γ Sge to δ Sge. The Dumbbell Nebula, M27, one of the brightest planetary nebulae, is in Vulpecula, 3.2° north of γ Sge, the tip of the Arrow.

O1.11.3Pegasus, Aquarius and Capricornus

The globular cluster M15 lies 4.2° north-west of Enif, the nose of Pegasus. M2, a slightly brighter globular cluster, lies 4.8° north of Sadalsuud (β Aqr). Further south, near Albali (ε Aqr), lie the globular cluster M72, 3.4° south-east of Albali, and M73, 4.2° south-east of Albali, which is only a group of four faint stars that Messier took for a cluster. The globular cluster M30, in Capricornus, lies 3.2° east of ζ Cap.

O1.11.4Andromeda, Triangulum, Cassiopeia and Perseus

Two lines through Mirach (β And) find the two great spiral galaxies of the Local Group. The line from Mirach to μ And, 3.9° long, carried on by the same length again, reaches M31, the Andromeda Galaxy, 7.7° from Mirach. Its two small companion galaxies lie close to it, M32 0.4° south and M110 0.6° north-west. The line from M31 through Mirach, carried on by about the same length, reaches M33, the Triangulum Galaxy, 7.1° beyond Mirach. M33 is large and faint, and is easier to see in binoculars than in a telescope at high magnification (Section O1.8).

In Cassiopeia, the open cluster M52 lies on the line from Schedar (α Cas) through Caph (β Cas), carried on a little more than as far again. The small cluster M103 is 1.0° north-east of Ruchbah (δ Cas). In Perseus, M34 is a bright open cluster 5.2° west of Algol, and the Little Dumbbell, M76, a faint planetary nebula, is 0.9° north of φ Per. South of these, in the autumn constellations Pisces and Cetus, lie two galaxies, M74 1.3° east of Alpherg (η Psc) and M77 0.9° south-east of δ Cet.

All 23 Messier objects of the section are listed below with their way from the nearest bright star.