Commission B2 Working Group on Designations

Helpful Hints:
Creating Acronyms

In all cases, before adopting a new acronym, be sure that it does not already exist in the Interactive Dictionary of Nomenclature.

There are several ways that acronyms can be created for the designation of sources. For example, they can be based on:

  1. Catalog Name

    Acronyms are often based on names of catalogues or surveys- such as NGC (The New General Catalogue) , FIRST (Faint Images of the Radio Sky at Twenty-cm), or CFRS (Canada-France Redshift Survey).

  2. Authors' Names

    The simplest form of an acronym is just one or more letters from the authors' names – such as Caswell (Caswell), WT (Wroblewski+Torres), RGH (Ramella+Geller+Huchra) , TeJu (Terzan+Ju), or PWP (Pauliny-Toth+Witzel+Preuss+).

  3. Types of Objects

    Although an acronym which uses "type of object" is appealing to astronomers for designating their sources and catalog, there is often a problem locating the reference later if more than one person has independently made such a catalog. For example, how do you find the reference for a particular OH source specified via OH LLL.lll+BB.bbb ? It could be in Turner's or Caswell's or someone else's list?

    However, if the community of researchers of a particular kind of object agree that this is "the catalog for such objects", then a designation with the acronym referring to that type of object is acceptable. The Reference Dictionary then keeps track of the future editions which may be published by different authors. Examples are PN (Planetary Nebula) which updates Perek+Kohoutek, 1967 (last version 1993) and HH (Herbig Haro obj.) begun by Herbig and Haro (1974) with a complete revision and extension of the numbering to numerous HH or HH-like objects by B. Reipurth.

  4. Observatories, Institutions, Instruments

    For large surveys and source catalogues undertaken by Observatories or other Institutions, it is quite appropriate to adopt an acronym based on the name of the Institute, Telescope, Instrument, etc. Examples include IRAS (Infrared Astronomical Satellite), HIP (Hipparcos catalogue), RX (Rosat satellite (X)), and ROTSE1 (Robotic Optical Transient Search Experiment, 1).

    However, if a survey is conducted or individual sources are found by individuals using an instrument (such as the VLA, HST) at an (inter)national Facility, then it is best not to use the acronym associated with that instrument unless the Facility expressly allows this (see comments about CXO in item 5). Instead, it is best to use the approach given in either items 1 and 2 above.

  5. Composite Ideas

    Sometimes acronyms are a combination of two different ideas – such as combining results from two instruments – an example is RGB (R from Rass for Rosat all sky survey and GB from Green Bank 5 GHz catalog) or catalogues and sources based on data obtained by individuals from an international Facility where the acronym is comprised of the authors' initials as well as the acronym associated with the instrument. Such an example is the Chandra X-ray Telescope which is detailed below (excerpted from their home page - with their permission):

    Chandra-Discovered Source Naming Convention

    The IAU Working Group Designations has approved the use of three acronyms for use in designation of sources found with the Chandra X-ray Observatory.

    CXO (Chandra X-ray Observatory) is reserved for designating sources from Chandra X-ray Center projects of an institutional nature.

    CXOAA, CXOAAA, and CXOAAAA are available for comprehensive source lists obtained from Chandra observations and made by individuals who pre-register the acronym using the IAU form at where they indicate the meaning of the appended characters, which are usually the initials of the author(s).

    CXOU where U means "unregistered" may be used for the occasional sources found/published by individuals using Chandra X-ray Observatory data.

    Sample Full Name (unregistered):

    CXOU Jhhmmss.s+ddmmss (e.g. CXOU J123456.7+765432)

    J indicates J2000 coordinates The coordinates should be truncated and are then accurate to 1.5", 1" for RA, Dec respectively.