| Legend | ||||
| Messier Catalog Column Descriptions | ||||
| Heading | Description | Heading | Description | |
| M | Messier Catalog Number | RA | Right Ascension (J2000) in Hours and Minutes | |
| NGC | New General Catalog Number | Dec | Declination (J2000) in Degrees and Minutes | |
| Type | Celestial Object Classification (see table below) | Con | IAU Constellation Abbreviation | |
| Mag | Apparent Visual Magnitude | Viewing Season |
Best Season for Viewing Messier Object | |
| Size | Angular Size in Arc-Minutes | Common Name |
Informal or Colloquial Name of Messier Object | |
| Distance | Distance from Solar System in Light Years | |||
| Messier Catalog Category Descriptions | ||||
| Type | Description | Type | Description | |
| OC | Open Cluster | SP | Spiral Galaxy | |
| GC | Globular Cluster | BA | Barred Galaxy | |
| PL | Planetary Nebula | LN | Lenticular Galaxy | |
| DI | Diffuse Nebula | EL | Elliptical Galaxy | |
| AS | Asterism | IR | Irregular Galaxy | |
| DS | Double Star | SN | Supernova Remnant | |
| MW | Milky Way Patch | |||