TimeUnixTai¶

class
astropy.time.
TimeUnixTai
(val1, val2, scale, precision, in_subfmt, out_subfmt, from_jd=False)[source]¶ Bases:
astropy.time.TimeUnix
Seconds from 19700101 00:00:08 TAI (see notes), including leap seconds.
This will generally differ from Unix time by the cumulative integral number of leap seconds since 19700101 UTC. This convention matches the definition for linux CLOCK_TAI (https://www.cl.cam.ac.uk/~mgk25/posixclocks.html).
Caveats:
Before 1972, fractional adjustments to UTC were made, so the difference between
unix
andunix_tai
time is no longer an integer.Because of the fractional adjustments, to be very precise,
unix_tai
is the number of seconds since19700101 00:00:08 TAI
or equivalently19691231 23:59:59.999918 UTC
. The difference between TAI and UTC at that epoch was 8.000082 sec.On the day of a leap second the difference between
unix
andunix_tai
times increases linearly through the day by 1.0. See also the documentation for theTimeUnix
class.
Examples
>>> from astropy.time import Time >>> t = Time('20200101', scale='utc') >>> t.unix_tai  t.unix 29.0
>>> t = Time('19700101', scale='utc') >>> t.unix_tai  t.unix 8.200000198854696e05
Attributes Summary
Return the cache associated with this instance.
Reference epoch time from which the time interval is measured
Time scale
Return time representation from internal jd1 and jd2.
Methods Summary
mask_if_needed
(value)set_jds
(val1, val2)Initialize the internal jd1 and jd2 attributes given val1 and val2.
to_value
([parent])Return time representation from internal jd1 and jd2.
Attributes Documentation

cache
¶ Return the cache associated with this instance.

epoch
¶ Reference epoch time from which the time interval is measured

epoch_format
= 'iso'¶

epoch_scale
= 'tai'¶

epoch_val
= '19700101 00:00:08'¶

epoch_val2
= None¶

in_subfmt
¶

jd1
¶

jd2
¶

jd2_filled
¶

mask
¶

masked
¶

name
= 'unix_tai'¶

out_subfmt
¶

scale
¶ Time scale

subfmts
= (('float', <class 'numpy.float64'>, None, <ufunc 'add'>), ('long', <class 'numpy.float128'>, <function longdouble_to_twoval>, <function twoval_to_longdouble>), ('decimal', <class 'numpy.object_'>, <numpy.vectorize object>, <numpy.vectorize object>), ('str', <class 'numpy.str_'>, <numpy.vectorize object>, <numpy.vectorize object>), ('bytes', <class 'numpy.bytes_'>, <numpy.vectorize object>, <numpy.vectorize object>))¶

unit
= 1.1574074074074073e05¶

value
¶
Methods Documentation

mask_if_needed
(value)¶

set_jds
(val1, val2)¶ Initialize the internal jd1 and jd2 attributes given val1 and val2. For an TimeFromEpoch subclass like TimeUnix these will be floats giving the effective seconds since an epoch time (e.g. 19700101 00:00:00).

to_value
(parent=None, **kwargs)¶ Return time representation from internal jd1 and jd2. Subclasses that require
parent
or to adjust the jds should override this method.