INTERNATIONAL EARTH ROTATION SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE BUREAU CENTRAL DE L'IERS OBSERVATOIRE DE PARIS Paris, 1 July 1996 61, Av. de l'Observatoire 75014 PARIS (France) Tel. (33) 1-40 51 22 26 Telex : 270776 OBS Internet : services@obspm.fr Span : MESIOA::SERVICES FAX : (33) 1 - 40 51 22 32 Bulletin C 12 To authorities responsible for the measurement and distribution of time INFORMATION ON UTC - TAI No positive leap second will be introduced at the end of December 1996. The difference between UTC and the International Atomic Time TAI is : from 1996 January 1, 0h UTC, until further notice : UTC-TAI = - 30 s 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. Martine FEISSEL Director Central Bureau of IERS