| Abbreviation | Definition |
|---|---|
| NGT | Next Generation Telescope |
| NI | Non-Impact |
| NIP | Normal Incidence Point |
| NIST | National Institute of Standards and Technology |
| NLST | National Large Solar Telescope |
| NMW | Northern Milky Way |
| NOAO | National Optical Astronomy Observatories |
| NOAO | National Optical Astronomy Observatory |
| NOC | No Observed Cone |
| NOMAD | Naval Observatory Merged Astrometric Dataset |
| NPC | Nice Planetary Contrast |
| NR | Non-Relativistic |
| NRAO | National Radio Astronomy Observatory |
| NS | Nearby Star |
| NS | Neutron Star |
| NSA | National Society of Astronomy |
| NSA | Neutron Star Atmosphere |
| NSAS | Northern Skies Astronomical Society |
| NSBD | Normal Stars and Brown Dwarfs |
| NSC | Nuclear Star Clusters |