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Long-term Delta T

Monthly determinations and long-term predictions of Delta T from finals.data are provided (ASCII).  Historic Delta T and LOD are also provided (ASCII).  Terrestrial Time (TT) is defined here.
 
Monthly values of (TT - UT1) since 1973.  Updated quarterly.
 
Predictions of (TT - UT1) from the present tthrough 2027.  Updated annually.
 
Provided by McCarthy and Babcock (1986)From 1657.0 to 1984.5.  

Plots of historic Delta T and historic length-of-day (LOD) are shown below.  Error bars are indicated in white.  Data points are shown in red.
 
deltat.pnglod.png

 


 
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