The catalogue
All 110 Messier objects
A list written in the 1770s by a comet hunter who was tired of being fooled — everything on it is here because it looked like a comet and was not. Two and a half centuries later it is still the list every amateur works through first, because Messier observed from Paris with a small refractor and so everything on it can be found with modest equipment from an imperfect sky. Each page gives what it takes to see that one, by sky and instrument.
Reading the numbers
Magnitude is all of an object's light added into a single number, as though it were a star. For a star that is exactly right. For anything with a size to it — a galaxy, a nebula, most of this list — it is close to useless on its own, because the same quantity of light spread over a larger area is harder to see, not easier.
Surface brightness is the number that decides it: how much light arrives per square arcsecond. The Andromeda Galaxy is magnitude 3.4, brighter than most stars you can name, and invisible from a city — because 190 by 60 arcminutes is an enormous area to spread it over. The Ring Nebula does the opposite: at magnitude 8.8 it is too faint for the naked eye, but it is small, so what light there is arrives concentrated and it stands out clearly in a telescope.
Both numbers are on every page here, along with what they work out to against nine grades of sky and five instruments. A darker site beats a bigger telescope more often than anyone selling telescopes will tell you.
Galaxies 40
- M31 Andromeda Galaxy The object that settled the largest argument in astronomy: in 1923 Edwin Hubble found a Cepheid… Andromeda 3.4
- M32 M32 A dwarf galaxy orbiting Andromeda, and probably what remains of something much larger after Andromeda took… Andromeda 8.1
- M33 Triangulum Galaxy The standard test of how dark a sky really is. Its light is spread so thinly… Triangulum 5.7
- M49 M49 Brightest of the fifteen hundred or so galaxies in the Virgo Cluster, and the earliest of… Virgo 8.4
- M51 Whirlpool Galaxy The first object in which anybody saw spiral structure — Lord Rosse drew it in 1845… Canes Venatici 8.4
- M58 M58 A barred spiral in Virgo, though at sixty million light-years the bar wants a good telescope… Virgo 9.7
- M59 M59 Koehler found this and M60 on the same night in April 1779, while he and Messier… Virgo 9.6
- M60 M60 A giant elliptical with a spiral apparently touching it, and unlike most such pairings this one… Virgo 8.8
- M61 M61 Seen almost face-on, which makes it photogenic and visually feeble at once — all that structure… Virgo 9.7
- M63 Sunflower Galaxy The Sunflower, and a flocculent spiral — not two clean arms but dozens of short patchy… Canes Venatici 8.6
- M64 Black Eye Galaxy The Black Eye, for a bank of dust lying across the front of the core and… Coma Berenices 8.5
- M65 M65 The tidy one of the Leo Triplet. Both its neighbours have been visibly knocked about by… Leo 9.3
- M66 M66 The big one of the Leo Triplet, and the one that took the damage — arms… Leo 8.9
- M74 Phantom Galaxy Widely considered the hardest object in the catalogue. It is a perfectly formed face-on spiral, which… Pisces 9.4
- M77 Cetus A The nearest bright Seyfert: a galaxy whose centre is lit by a black hole actively feeding… Cetus 8.9
- M81 Bode's Galaxy A near-perfect grand-design spiral and one of the brightest galaxies in the sky. Ursa Major 6.9
- M82 Cigar Galaxy M81 came too close a few hundred million years ago, and this is the result: star… Ursa Major 8.4
- M83 Southern Pinwheel The Southern Pinwheel, near enough that individual knots of star formation turn up in amateur photographs. Hydra 7.6
- M84 M84 One end of Markarian's Chain, a curving line of galaxies that fits inside a single low-power… Virgo 9.1
- M85 M85 The northernmost of the Virgo galaxies, and a lenticular — the disc of a spiral with… Coma Berenices 9.1
- M86 M86 Falling through the Virgo Cluster fast enough to be coming at us, which makes it one… Virgo 8.9
- M87 Virgo A Heber Curtis photographed what he called a curious straight ray coming out of this galaxy in… Virgo 8.6
- M88 M88 Tilted about halfway to edge-on, which happens to be the angle that most resembles what people… Coma Berenices 9.6
- M89 M89 The roundest elliptical known, at least from where we happen to be standing. Virgo 9.8
- M90 M90 A large spiral in the process of dying: the cluster has taken most of its gas… Virgo 9.5
- M91 M91 Lost for two hundred years: Messier measured its position from M89 and then applied the figures… Coma Berenices 10.2
- M94 Cat's Eye Galaxy A bright inner ring of furious star formation surrounded by a much fainter outer disc, which… Canes Venatici 8.2
- M95 M95 A barred spiral with a ring of star formation around the core, textbook enough that it… Leo 9.7
- M96 M96 The brightest galaxy of the Leo I group, and a visibly lopsided one — arms and… Leo 9.2
- M98 M98 Coming toward us at 140 kilometres a second, which makes it one of a handful of… Coma Berenices 10.1
- M99 M99 Among the first galaxies in which anyone recognised spiral structure, drawn by Lord Rosse shortly after… Coma Berenices 9.9
- M100 M100 The galaxy that pinned down how fast the universe is expanding: in 1994 the newly repaired… Coma Berenices 9.3
- M101 Pinwheel Galaxy A vast face-on spiral, nearly twice the width of our own galaxy, and notoriously disappointing at… Ursa Major 7.9
- M102 Spindle Galaxy A genuine unsolved entry. Méchain later wrote that it had been a duplicate observation of M101… Draco 9.9
- M104 Sombrero Galaxy The Sombrero, six degrees off edge-on, with a dust lane so sharp it looks ruled on. Virgo 8.0
- M105 M105 One of the best-measured black holes anywhere sits at the centre of this one — around… Leo 9.3
- M106 M106 A spiral with two extra arms made of glowing gas rather than stars, blown out by… Canes Venatici 8.4
- M108 M108 A streak rather than a shape: edge-on, mottled with dust, and with no core showing at… Ursa Major 10.0
- M109 M109 The most distant galaxy in the catalogue, and a barred spiral broadly like the one we… Ursa Major 9.8
- M110 M110 Messier drew this one in 1773 and then, for reasons nobody has established, left it off… Andromeda 8.5
Globular clusters 29
- M2 M2 Maraldi found it on 11 September 1746 while chasing a comet, and Messier found it again… Aquarius 6.5
- M3 M3 The first object Messier found himself rather than borrowed from somebody else's list, and the one… Canes Venatici 6.2
- M4 M4 The only globular on Messier's list that Messier could actually resolve — he wrote it down… Scorpius 5.6
- M5 M5 Around thirteen billion years old, which makes it older than the disc of the galaxy it… Serpens 5.6
- M9 M9 There is a wall of dust between us and this one, thick enough to steal about… Ophiuchus 7.7
- M10 M10 One of a pair with M12, three degrees apart, near enough that a wide field takes… Ophiuchus 6.6
- M12 M12 A cluster that has been robbed. Repeated passes through the disc of the galaxy have stripped… Ophiuchus 6.7
- M13 Hercules Cluster The showpiece globular of northern skies, and the target of the Arecibo message in 1974 … Hercules 5.8
- M14 M14 In 1964 Amelia Wehlau found a nova on plates of this cluster that Helen Sawyer Hogg… Ophiuchus 7.6
- M15 M15 The core of this one has fallen in on itself, and the stars at the centre… Pegasus 6.2
- M19 M19 The most oblate globular known — you can count twice as many stars along its long… Ophiuchus 6.8
- M22 M22 Brighter and larger than M13 and almost unknown by comparison, entirely because it sits low in… Sagittarius 5.1
- M28 M28 In 1987 this cluster gave up the first millisecond pulsar ever found inside a globular … Sagittarius 6.8
- M30 M30 Another collapsed core, with two thin chains of stars trailing away — the marks of having… Capricornus 7.2
- M53 M53 Far out toward the edge of what our galaxy still holds, and made almost entirely of… Coma Berenices 7.6
- M54 M54 For two centuries an ordinary if distant globular. In 1994 the Sagittarius Dwarf Galaxy was discovered… Sagittarius 7.6
- M55 M55 A large, loose globular that resolves into stars more readily than almost any other, because it… Sagittarius 6.3
- M56 M56 A small, unassuming globular halfway between Albireo and the Ring Nebula, both of which are more… Lyra 8.3
- M62 M62 Visibly lopsided, its core shoved off-centre by repeated close passes to the middle of the galaxy. Ophiuchus 6.5
- M68 M68 A southern globular that never climbs far from northern latitudes and is ignored for it. Hydra 7.8
- M69 M69 Unusually rich in heavy elements for a globular, which means it formed later than most of… Sagittarius 7.6
- M70 M70 A near twin of M69 two and a half degrees away, and the accidental site of… Sagittarius 7.9
- M71 M71 Argued about for two centuries — too loose for a globular, too rich for an open… Sagitta 8.2
- M72 M72 About as faint and as remote as this catalogue goes for globulars, out in the galaxy's… Aquarius 9.4
- M75 M75 The most remote globular in the catalogue that actually belongs to our galaxy. Sagittarius 8.5
- M79 M79 A globular sitting in the winter sky, where globulars have no business being: they crowd around… Lepus 7.7
- M80 M80 In May 1860 a star inside this cluster flared up and briefly outshone the whole of… Scorpius 7.3
- M92 M92 A superb globular that would be famous anywhere else in the sky, and is instead nine… Hercules 6.4
- M107 M107 Méchain found it in 1782 and it then sat outside the catalogue for a century and… Ophiuchus 8.1
Open clusters 26
- M6 Butterfly Cluster The Butterfly, and for once the name earns itself — the wings are there at almost… Scorpius 4.2
- M7 Ptolemy's Cluster Ptolemy logged this as a cloudy patch in AD 130, which is why it still carries… Scorpius 3.3
- M11 Wild Duck Cluster The Wild Duck, named by Admiral Smyth in the 1840s for a V of brighter stars… Scutum 6.3
- M18 M18 A sparse scattering of about twenty stars, catalogued because it sits between M17 and M24 in… Sagittarius 7.5
- M21 M21 Five million years old, which for a cluster is infancy — nothing in it has had… Sagittarius 6.5
- M23 M23 A hundred-odd stars spread evenly with no real centre, which makes it better in binoculars than… Sagittarius 5.5
- M25 M25 Somewhere in this loose scattering sits U Sagittarii, a Cepheid that brightens and fades on a… Sagittarius 4.6
- M26 M26 Modest, and unluckily placed a few degrees from M11, which is far better and gets looked… Scutum 8.0
- M29 M29 Half a dozen stars in a rough box, and one of the weakest entries in the… Cygnus 6.6
- M34 M34 A wide, loose scattering that wants low power and a wide field, and is spoiled by… Perseus 5.5
- M35 M35 Large and rich, and with a bonus: the small, much more distant cluster NGC 2158 sits… Gemini 5.3
- M36 M36 The youngest of the three clusters strung across Auriga at about 25 million years — too… Auriga 6.3
- M37 M37 The best of the three Auriga clusters by a clear margin — several hundred stars, dense… Auriga 6.2
- M38 M38 The faintest of the Auriga three, its brighter stars falling into a rough cross. Auriga 7.4
- M39 M39 Thirty-odd stars spread over most of a Moon-width, and so loose that magnification destroys it. Cygnus 4.6
- M41 M41 Aristotle may have written this down around 325 BC, describing something below Sirius as a star… Canis Major 4.5
- M44 Beehive Cluster The Beehive, and one of the few things here with a practical use: the Greeks watched… Cancer 3.1
- M45 Pleiades The Pleiades, recorded by every culture that has ever written anything down. Taurus 1.2
- M46 M46 A rich cluster with a planetary nebula, NGC 2438, apparently sitting inside it — apparently, because… Puppis 6.1
- M47 M47 A lost Messier: he wrote the position down with a sign error and nothing was there… Puppis 4.4
- M48 M48 Lost for the same reason as M47 — a recording error put it five degrees from… Hydra 5.8
- M50 M50 A heart-shaped scattering of about a hundred stars with one conspicuously red one on its southern… Monoceros 5.9
- M52 M52 Bright on paper and awkward in practice, because it sits in a stretch of Milky Way… Cassiopeia 6.9
- M67 M67 Four billion years old, where most open clusters come apart within a few hundred million. Cancer 6.1
- M93 M93 A compact wedge of about eighty stars, with a pair of orange giants near the middle… Puppis 6.2
- M103 M103 The last entry in the catalogue as Messier published it — everything above 103 was added… Cassiopeia 7.4
Nebulae 7
- M8 Lagoon Nebula The dark lane that gives the Lagoon its name is not a gap in the cloud… Sagittarius 4.6
- M16 Eagle Nebula The Eagle Nebula, and the site of the Pillars of Creation — the Hubble photograph that… Serpens 6.0
- M17 Omega Nebula Called the Omega, the Swan and the Horseshoe by different people looking at the same bar… Sagittarius 6.0
- M20 Trifid Nebula The Trifid's three dark lanes are dust in front of the glow, not gaps in it. Sagittarius 6.3
- M42 Orion Nebula Not really a cloud at all: it is a hollow cavity blown into the side of… Orion 4.0
- M43 De Mairan's Nebula Part of the Orion Nebula, and separate only because a lane of foreground dust makes it… Orion 9.0
- M78 M78 The brightest reflection nebula there is, and it makes no light of its own — only… Orion 8.3
Planetary nebulae 4
- M27 Dumbbell Nebula The first planetary nebula anybody found, and still the finest. Vulpecula 7.4
- M57 Ring Nebula The object that saddled planetary nebulae with their wrong name: through early telescopes the little disc… Lyra 8.8
- M76 Little Dumbbell Among the faintest things in the catalogue: a smaller, dimmer M27 with the same two lobes… Perseus 10.1
- M97 Owl Nebula The Owl, for two darker patches in the disc that read as eyes — an impression… Ursa Major 9.9
Supernova remnants 1
Asterisms 3
- M24 Sagittarius Star Cloud Not an object at all but a hole in the dust — a window through the… Sagittarius 2.5
- M40 Winnecke 4 A mistake, preserved. Messier went looking for a nebula another astronomer had reported here, found nothing… Ursa Major 8.4
- M73 M73 Four faint stars in a Y, and nothing else. Messier suspected there was nebulosity between them… Aquarius 9.0