Dictionary of Nomenclature of Celestial Objects
(Last update: 10-Apr-2017)

Result of query: info cati USNO-A2.0$

Details on Acronym:   USNO-A2.0
   USNO-A2.0 (US Naval Obs., A2.0 catalogue) Write:<<USNO-A2.0 NNNN-NNNNNNNN>> N: 526280881 Object:*  (SIMBAD class: Star) Note:USNO-A2.0 is based on a re-reduction of the Precision Measuring Machine (PMM) scans from POSS-I O and E plates (≥-18deg) and SRC-J and ESO-R plates (≤-20deg).
The major difference between USNO-A2.0 and its previous version USNO-A1.0 is that A1.0 used the Guide Star Catalog as its reference frame whereas A2.0 uses the ICRF as realized by the USNO ACT catalog (Urban et al. 1997).
The USNO-A2.0 number is made of a zone number (4 digits from 0000 to 1725 representing the distance in 0.1deg to the South Pole) and a number in the area (8 digits); a dash - must separate the two parts. Note that this number differs from the USNO-A1.0 number. Ref:=1998USNO2.C......0M byMONET D. , et al. The PMM USNO-A2.0 Catalog., 0 (1998) A catalogue of astrometric standards. o<USNO-A2.0 NNNN-NNNNNNNN> N=526280881. =E=Catalogue in electronic form as I/252 Originof the Acronym: A = Assigned by the author(s)