Principal name: objname

The principal name is normally chosen descending the following hierarchy: NGC - IC - UGC - ESO - HD - BD - PGC - Others. But it also avoids designations considered as non-reliable (for example designations used for multiple objects or those which were found in disagreement with the identification made by NED).

We recommend that authors of tables or catalogues identify their objects with the principal name, the celestial position plus possibly a name specific to the context (for example in a paper studying 3C sources use also the 3C name). Such a redundancy may appear excessive, but we have many examples where the identification provided by the authors is ambiguous and prevent the cross-identification with the databases.