Earth Orientation Products
USNO, as the IERS Rapid Service/Prediction Center, provides daily, weekly, and long-term data products. Data files and plots are categorized into daily, weekly, and long-term products. The Bulletin A, updated every Thursday, is available here. An archive of past issues of Bulletin A is here. If you would like to receive (or unsubscribe from) the Bulletin A electronically, use the document request form.
Daily Solutions
Daily data files available by anonymous ftp. Updated daily
(normally around 17:05 UTC), for highest accuracy real-time applications.
Weekly Solutions
Standard data files available by anonymous ftp. Updated weekly
on Thursdays. Plots of Bulletin A combination and residuals. Statistical report for contributed series.
Long-term Delta T
Monthly determination of Delta T (TT - UT1) since 1973 and long-term predictions. Determinations of Delta T are updated approximately quarterly, and long-term predictions from finals.data are updated annually.
