Category:88 IAU-Constellations

Over the course of the decade of the 1920s, the IAU officially defined the borders of the constellations as lines of constant right ascension and declination (for the equator and equinox of B1875.0). This definition is used as international standard in research papers.

However, there is no single date of the definition but there are actually some very important dates:

1. 1922 The international standardization of 89 Latin constellation names:
   1. in Nominativ, Genitiv and their three-letter-abbreviation.
   2. Argo, Arg included: important for historians!
2. 1925 Delporte's presentation of his definition of border lines.
3. 1928 the acceptance of Delporte's suggestion.
4. 1930 publication of Delporte's detailed specification of the constellation borders with an accompanying celestial atlas.

The origins of these constellations are diverse.