imap_processing.spice.time.ttj2000ns_to_met#
- imap_processing.spice.time.ttj2000ns_to_met(tt_ns: _Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes]) ndarray[tuple[int, ...], dtype[float]]#
Convert terrestrial time nanoseconds since J2000 to mission elapsed time (MET).
This is the inverse of met_to_ttj2000ns. The conversion process is: TTJ2000ns -> ET -> MET
- Parameters:
tt_ns (float, numpy.ndarray) – Number of nanoseconds since the J2000 epoch in the TT timescale.
- Returns:
The mission elapsed time in seconds.
- Return type: