imap_processing.idex.idex_l1a.calculate_idex_event_time

imap_processing.idex.idex_l1a.calculate_idex_event_time(coarse_time_sec: ndarray, fine_time_subs: ndarray) → ndarray[tuple[int, ...], dtype[int64]]

Calculate the epoch time from the FPGA header time variables.

Coarse_time_sec counts the number of whole seconds elapsed since the epoch (Jan 1st 2010), while fine_time_subs counts the number of additional 20-microsecond intervals beyond the whole seconds. Together, these time measurements establish when a dust event took place.

Parameters:

• coarse_time_sec (numpy.ndarray) – The coarse event time (seconds).

• fine_time_subs (numpy.ndarray) – The fine event time in 20-microsecond intervals.

Returns:

The mission elapsed time converted to nanoseconds since the J2000 epoch in the terrestrial time (TT) timescale.

Return type:

numpy.ndarray[numpy.int64]