[Bulletins]
IERS  Bulletins  A  and  Bulletin  B/C04  provide  values  of  the  Earth's  orientation  parameters  in  the  IERS 
Reference System including UT1-UTC,  coordinates of the terrestrial pole, and celestial pole offsets. Bulletin A 
is issued weekly by the IERS Rapid Service/Prediction Center at the U.S. Naval Observatory, Washington, DC. 
It provides the most recently observed estimates as well as predictions of Earth Orientation Parameters (EOPs). 
Bulletin B/C04 is issued monthly by the IERS Earth Orientation Centre (EOC) at the Paris Observatory, and 
provides daily data covering a period from several decades to 30 days previous to the date of publication.. The 
Earth orientation parameters provided in Bulletins A and B may be used to relate the International Celestial and 
Terrestrial  Reference  Systems  as  realized  operationally  by  the  International  and  Celestial  Reference  Frames 
respectively.  The  rigorous  details  are  outlined  in  the  publications  of  the  International  Earth  Rotation  and 
Reference  Systems  Service  (IERS),  specifically  in  the  IERS  Conventions  (2010)  and  its updates  (see below), 
which are available electronically at http://tai.bipm.org/iers/conv2010/conv2010.html.5. A full description of all 
of the IERS products is available at the IERS web site [www.iers.org].