# LeapSeconds.jl

`LeapSeconds.offset_tai_utc`

— Function`offset_tai_utc(tai1, tai2=0.0)`

Returns the difference between International Atomic Time (TAI) and Coordinated Universal Time (UTC) for a given TAI Julian day number `tai1`

(optionally split into two parts for increased precision).

$\Delta AT = TAI - UTC$

`LeapSeconds.offset_tai_utc`

— Method`offset_tai_utc(dt::DateTime)`

Returns the difference between International Atomic Time (TAI) and Coordinated Universal Time (UTC) for a given `DateTime`

in TAI.

$\Delta AT = TAI - UTC$

`LeapSeconds.offset_utc_tai`

— Function`offset_utc_tai(utc1, utc2=0.0)`

Returns the difference between Coordinated Universal Time (UTC) and International Atomic Time (TAI) for a given UTC pseudo-Julian day number `utc1`

(optionally split into two parts for increased precision).

$\Delta AT = UTC - TAI$

This function uses the ERFA convention for Julian day numbers representing UTC dates during leap seconds.

`LeapSeconds.offset_utc_tai`

— Method`offset_utc_tai(dt::DateTime)`

Returns the difference between Coordinated Universal Time (UTC) and International Atomic Time (TAI) for a given `DateTime`

in UTC.

$\Delta AT = UTC - TAI$

The `DateTime`

type from Julia's Standard Libary cannot represent UTC dates during leap seconds, e.g. "2016-12-31T23:59:60.0" will not be parsed as a valid `DateTime`

but throw an error. The AstroTime.jl package provides a leap second-aware `Epoch`

type that can be used as a replacement.