SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE
BUREAU CENTRAL DE L'IERS
OBSERVATOIRE DE PARIS
61, Av. de l'Observatoire 75014 PARIS (France)
Tel. : 33 (0) 1 40 51 22 26
FAX : 33 (0) 1 40 51 22 91
Internet : iers@obspm.fr
Paris, 17 July 1998
Bulletin C 16
To authorities responsible for
the measurement and distribution
of time
UTC TIME STEP
on the 1st of January 1999
A positive leap second will be introduced at the end of December 1998.
The sequence of dates of the UTC second markers will be:
1998 December 31, 23h 59m 59s
1998 December 31, 23h 59m 60s
1999 January 1, 0h 0m 0s
The difference between UTC and the International Atomic Time TAI is:
from 1997 July 1, 0h UTC, to 1999 January 1, 0h UTC : UTC-TAI = - 31s
from 1999 January 1, 0h UTC, until further notice : UTC-TAI = - 32s
Leap seconds can be introduced in UTC at the end of the months of
December or June, depending on the evolution of UT1-TAI. Bulletin C mailed
every six months, either to announce a time step in UTC, or to confirm that
there will be no time step at the next possible date.
Daniel GAMBIS
Director
Central Bureau of IERS
