utc_from_tai_unix¶
- lsst.ts.utils.utc_from_tai_unix(tai_unix: float) float¶
Return UTC in unix seconds, given TAI in unix seconds.
The difference is always an integer. Thus this is not the inverse of
tai_from_utc_unix, because that function smears UTC time on the day before a leap second.- Parameters:
- tai_unix
float TAI time in unix seconds.
- tai_unix
- Returns:
- utc_unix
float UTC time in unix seconds.
- utc_unix
- Raises:
- ValueError
If the date is earlier than 1972 (which is before integer leap seconds) or within one day of the expiration date of the leap second table (which is automatically updated).
Notes
This function uses a leap second table that is automatically updated in the background (though updates are very infrequent).