Computation of GAST, GMST, and ERA

This service computes GAST (Greenwich Apparent Sidereal Time), GMST (Greenwich Mean Sidereal Time), and ERA (Earth Rotation Angle), time-related quantities required for, e.g., many uses of our APFS service. To learn more, see the service info or the web page of the IERS.

To compute the current values, leave the form empty. Otherwise, enter a date expression (for UT1; only a subset of the available operators is supported) and an interval (in seconds) for how often a date should be computed.

Examples:

Date and time (UT1)
Interval between two sets of computed values

The Data Center is currently running in emergency mode after our database server failed catastrophically (see our blog for infos and updates).

This means, in particular, that services built on top of large tables may currently be broken. Since our replacement server is much slower than our usual machine, restoring them will take quite some time.

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