Planets & Deep Sky
What Are Messier Objects and How to Start the Messier List
Discover what Messier objects are, why Charles Messier catalogued 110 galaxies, nebulae, and clusters, and how beginners can start checking them off tonight.
Messier objects are a collection of 110 galaxies, nebulae, and star clusters that French astronomer Charles Messier catalogued in the 1700s. They are among the easiest deep-sky objects to find, and working through the list is one of the best ways to get comfortable with your telescope and the night sky.
At a Glance
- The catalog holds 110 objects, labeled M1 through M110, built up between 1774 and the final additions confirmed in 1967.
- Objects fall into three broad categories: galaxies, nebulae (emission, planetary, and supernova remnants), and star clusters (open and globular).
- Most of the list is reachable with a 70-80mm refractor, a small reflector, or even binoculars from a reasonably dark sky.
- Star-hopping with a printed chart, protected by a red flashlight, is still the most reliable way to find them.
- The Messier Marathon, a mid-March attempt to see all 110 objects in one night, is possible only from roughly 25 to 35 degrees north latitude.
- The Astronomical League's Messier Program offers a free certificate for completing the list, a good milestone for a first full season of deep-sky observing.
Who Was Charles Messier?
Charles Messier (1730-1817) was a comet hunter. He spent years sweeping the sky looking for new comets, and he kept running into the same fuzzy blobs that were not comets at all. Rather than keep mistaking them for his targets, he started writing them down.
The first edition of his catalog appeared in 1774 with 45 objects. He eventually built it to 103 entries, with later astronomers confirming a handful of additional objects he had observed but not formally included. According to the catalog's full modern history, the accepted list reached its current 110 objects only in 1967, when Kenneth Glyn Jones added M110 based on notes in Messier's own papers; earlier additions came from Camille Flammarion in 1921 and Helen Sawyer Hogg in 1947.
Messier never intended to create a guide for amateur astronomers. He was just clearing the sky of distractions. But the side effect is that his list concentrates some of the finest objects in the northern and equatorial sky into a single, well-documented catalog, and nearly all of them are within reach of a small telescope.
What the Catalog Contains
The 110 Messier objects fall into a few main categories.
Galaxies make up the largest portion of the catalog, roughly 40 of the 110 entries. The list includes spirals, ellipticals, and irregular galaxies. M31, the Andromeda Galaxy, is the most distant object visible to the naked eye from a dark site. M81 and M82 in Ursa Major are a well-matched pair you can fit in the same low-power field. M104, the Sombrero Galaxy, shows a dark dust lane even through modest aperture.
Nebulae come in several forms. Emission nebulae like M42 (the Orion Nebula) glow because young stars ionize the surrounding gas. Planetary nebulae such as M57 (the Ring Nebula) are shells of gas shed by dying stars. Supernova remnants like M1 (the Crab Nebula) mark where a star exploded in 1054 CE, an event recorded by Chinese astronomers.
Star clusters split into two types. Open clusters like M45 (the Pleiades) are loose groups of young stars still near their birthplace, usually a few hundred million years old or younger. Globular clusters like M13 in Hercules are tight, ancient spheres holding hundreds of thousands of stars bound by mutual gravity, some of the oldest structures in the galaxy at over 10 billion years.
The catalog covers objects spread across nearly every part of the sky accessible from mid-northern latitudes, with a concentration toward the heart of the Milky Way in Sagittarius, where you will find more than a dozen targets packed into a small area.
The Catalog by the Numbers
| Category | Approximate count | Example |
|---|---|---|
| Galaxies | 40 | M31, Andromeda Galaxy |
| Open clusters | 27 | M45, the Pleiades |
| Globular clusters | 29 | M13, Hercules Cluster |
| Diffuse (emission/reflection) nebulae | 7 | M42, Orion Nebula |
| Planetary nebulae | 4 | M57, Ring Nebula |
| Supernova remnant | 1 | M1, Crab Nebula |
| Double star | 1 | M40 |
| Asterism (not a real deep-sky object) | 1 | M73 |
How to Start Observing Messier Objects
Choose your equipment
Most Messier objects are accessible with binoculars or a small telescope. A 70-80mm refractor or a 114-130mm reflector will show every object on the list from a reasonably dark suburban sky. Larger aperture improves contrast and reveals finer detail, but the priority at first is getting familiar with star-hopping and finding things, not chasing the limits of your optics.
A low-power, wide-field eyepiece works best for most targets. When you hunt a small but bright object like M57, you can switch to higher magnification. For sweeping large nebulae and clusters, keep the power low.
Learn to star-hop
The most reliable way to find Messier objects is star-hopping: you start from a bright star you can identify, then step across a series of progressively dimmer stars until you reach the target. Printed charts work well for this. A planisphere or a printed star atlas like Sky & Telescope's Pocket Sky Atlas shows the surrounding field clearly without a screen draining your night vision.
Red-light flashlights let you read charts without disrupting your dark adaptation. White light resets your dark-adapted eyes quickly, so avoid it. Dark adaptation itself takes 20 to 30 minutes to build up and can be undone by a single glance at a bright screen, which is the main reason experienced Messier hunters guard their red light so carefully.
If you use a phone app, dim the display as far as it will go and switch on any night-mode setting available. A bright screen even a few inches from your face will cost you several minutes of dark adaptation each time you look at it.
Keep a log
Write down what you see for each object: date, time, magnification, sky conditions, and a brief description. It sounds tedious but it pays off. You will notice patterns in how different object types look, and a log gives you something concrete when you revisit a target in better conditions. A simple notebook works as well as any dedicated observing app.
If you want to make it official, the Astronomical League's Messier Observing Program offers two certificate tiers: a Silver-level certificate for logging 70 of the 110 objects, and a Gold-level certificate plus pin for completing all 110, each verified by a society officer or qualified reviewer. The program's rules specifically exclude automated GoTo slews from counting toward the award, since the point is learning to find things yourself. Joining a local astronomy club connects you with experienced observers who have already worked the catalog and can show you the trickier targets.
The Messier Marathon
Once a year, usually in mid-March around new moon, it becomes possible to observe all 110 Messier objects in a single night. This is the Messier Marathon.
The geometry works because in mid-March the Sun sits at a point in the sky roughly opposite the large concentration of Messier objects in Virgo, Coma Berenices, and Sagittarius. The Virgo objects set after sunset while the Sagittarius cluster rises before sunrise, giving an observer at a latitude of about 25 to 35 degrees north a window to catch every target.
The marathon requires serious preparation: dark skies with no Moon, a complete list sorted by time of observation, and ideally a location with flat horizons to the east and west. You begin in the west at dusk hunting objects low in the evening sky before they set, work through the night, and finish by racing to catch the Sagittarius objects rising in the southeast before the sky brightens.
A successful marathon under good conditions from a mid-latitude site requires moving efficiently through the list, often no more than a few minutes per object once the pace picks up after midnight. Observers at high northern latitudes (above 50 degrees) cannot complete the full marathon because a few far-south objects, such as M7 in Scorpius, never rise high enough above the horizon haze to see clearly.
Even attempting a marathon without finishing it is a good exercise. You will see more sky in one night than most beginners see in their first year.
A Starter List of Easy Messier Objects
If you are new to the catalog, these six targets are worth finding first. They are large, bright, and forgiving of mediocre skies.
| Object | Type | Constellation | Notes |
|---|---|---|---|
| M45 (Pleiades) | Open cluster | Taurus | Naked-eye target; binoculars show dozens of stars and subtle nebulosity |
| M42 (Orion Nebula) | Emission nebula | Orion | The best nebula in the sky; visible to the naked eye as the fuzzy middle "star" in Orion's sword |
| M31 (Andromeda Galaxy) | Galaxy | Andromeda | Largest naked-eye galaxy; 2.5 million light-years away; look for its satellite galaxies M32 and M110 nearby |
| M13 (Great Hercules Cluster) | Globular cluster | Hercules | Brightest globular in the northern sky; a telescope resolves it into stars at the edges |
| M57 (Ring Nebula) | Planetary nebula | Lyra | Small smoke ring easily visible at moderate magnification; lies between the two southern stars of the Lyra parallelogram |
| M81/M82 | Galaxy pair | Ursa Major | Fit in the same wide-field view; M82 shows a ragged, cigar shape distinct from M81's smooth spiral |
Once you have found these, consider moving to the other bright objects across the sky. If you want to understand the planets in more detail before tackling deep sky, learning how to see Saturn's rings through a telescope builds useful telescope skills that transfer directly to finding faint fuzzies. Similarly, the techniques for observing Jupiter and its four Galilean moons will sharpen your ability to track down objects by their position relative to nearby stars. For purely lunar practice, studying the Moon's craters, maria, and the terminator is the fastest way to get comfortable with your eyepieces before moving on to deep sky.
Frequently Asked Questions
How long does it take to complete the Messier catalog?
It depends on how often you observe and what sky access you have. Many people work through the entire list over one to three years, picking off accessible objects through the seasons. Dedicated observers with dark skies have completed it in a few months. The full catalog spans enough of the sky that some objects only become well-placed at certain times of year, so rushing it means missing optimal conditions for some targets.
Do I need a telescope to observe Messier objects?
No. About 40 objects on the list are visible to the naked eye from a dark site, and many more are easily seen through binoculars. Binoculars are particularly useful for large objects like M31, M45, and M44 (the Beehive Cluster), which appear more impressive in a wide field than through a narrow telescope view. A telescope is needed for fainter objects and for resolving detail.
What is the hardest object on the Messier list?
M74, a face-on spiral galaxy in Pisces, is widely considered the toughest target on the list. It has a low surface brightness spread across a large area, making it nearly invisible from suburban skies. M77 and M101 are similarly difficult. These objects reward dark skies far more than extra aperture.
Can I observe Messier objects from the city?
You can find many of them. Star clusters and some of the brighter galaxies survive suburban skies reasonably well. Extended nebulae like M33 (the Triangulum Galaxy) and low-surface-brightness objects become nearly impossible once light pollution brightens the background sky. For city observers, the open clusters and globulars make the most satisfying targets.
What is the difference between a Messier object and an NGC object?
The New General Catalogue (NGC) is a later, much larger catalog compiled by John Louis Emil Dreyer in 1888, containing nearly 8,000 objects. Every Messier object also has an NGC designation. The Messier catalog is a curated shortlist of the showpiece targets; the NGC covers a far wider range of objects, including many that require larger aperture to see at all.
Do I need to log objects a certain way to qualify for the Astronomical League's certificate?
Yes. The program asks for the date, time, and location of each observation, the instrument and magnification used, sky conditions, and a short description of what you actually saw, not a copied catalog description. A sponsoring society officer or the League's own reviewers check submissions before issuing the certificate, and observations made purely by letting an automated GoTo mount find the object do not count.
What order should I observe the Messier objects in?
There is no required order, but a seasonal approach works well for beginners: focus on whatever constellations are highest in the evening sky each month rather than working straight through the catalog numbers, since M1 and M110 are not near each other in the sky or in difficulty. Grouping targets by constellation also cuts down on how much you have to move the mount or re-orient a star chart in a single session.