The Messier Catalog is a collection of 110 deep-sky objects—galaxies, nebulae, and star clusters—compiled in the 18th century by French astronomer Charles Messier to help observers distinguish permanent celestial objects from comets. Because Messier observed from Paris, most of his catalog highlights objects visible in the Northern Hemisphere. While a few famous Messier objects—like the Andromeda Galaxy (M31), Orion Nebula (M42), and the Pleiades (M45)—are visible to the naked eye under dark skies, most require binoculars or a telescope to truly appreciate.

The chart below shows how Messier objects are distributed in declination across the year, and the interactive tool that follows helps you explore which ones are visible from your latitude and which are highest in your sky at midnight for each month.

Explore my Interactive Messier Sky Planner

Not everyone shares the same sky. Because Earth is curved, your latitude determines how high each Messier object climbs—and some may never rise at all from where you are. This interactive planner reveals which Messier objects are visible from your location and ranks them by how high they stand at midnight in each month.

Finding Deep-Sky Objects with RA and DEC

Right Ascension (RA) and Declination (DEC) are the celestial equivalent of longitude and latitude on Earth, used to pinpoint the exact position of an object in the night sky. RA measures how far east an object is along the celestial equator, expressed in hours, minutes, and seconds (since the sky appears to rotate once every 24 hours), while DEC measures how far north or south an object lies, in degrees. If your telescope is mounted on an equatorial mount, you can use the RA and DEC setting circles—or your mount’s computerized GoTo system—to align and move directly to these coordinates. To make this work accurately, your mount must first be polar aligned, meaning its RA axis is aimed precisely at the celestial pole (near Polaris in the Northern Hemisphere). Once properly aligned, tracking in RA allows your telescope to follow the object smoothly as the Earth rotates.

Finally, you’ll find the full Messier catalog, covering objects from M1 to M110. Use the search function to quickly locate any target by its Messier or NGC number, constellation, or nickname. You can also filter by object type—such as galaxies, nebulae, or clusters—and view precise RA and DEC coordinates to help your telescope mount automatically slew to the chosen object.