| Obj. Type | Acronym | (Explanation) | Format | ||
| E | ? | N | (Abbreviation of NGC) | NGC NNNNA | |
| E | ? | NGC | (New General Catalog) | NGC NNNN
NGC NNNNA NGC NNNNAA (L) | |
| E | ? | RNGC | (Revised New General Catalog) | NGC NNNNA |
Acronyms flagged by E are available in electronic form at CDS
(L) following the Format indicates a form found later in the literature, which is not recognized by SIMBAD.