From jim.ray at noaa.gov Mon Jul 7 06:14:15 2008 From: jim.ray at noaa.gov (Jim.Ray) Date: Mon, 07 Jul 2008 09:14:15 -0400 Subject: [IGSMAIL-5789]: Leap Second Announcement (IERS Bulletin C36) Message-ID: <487216A7.5030801@noaa.gov> ****************************************************************************** IGS Electronic Mail 07 Jul 06:14:22 PDT 2008 Message Number 5789 ****************************************************************************** Author: Jim Ray (forward IERS Bulletin C36) Users should consider updating their leap second control files for the next one on 31 December 2008. After that epoch, the following will apply: TAI - UTC = 34 s (after 31 Dec 2008) GPS Time - UTC = 15 s (modulo seconds, after 31 Dec 2008) -------------------------------------------------------------------- INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE 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 e-mail : services.iers at obspm.fr http://hpiers.obspm.fr/eop-pc Paris, 4 July 2008 Bulletin C 36 To authorities responsible for the measurement and distribution of time UTC TIME STEP on the 1st of January 2009 A positive leap second will be introduced at the end of December 2008. The sequence of dates of the UTC second markers will be: 2008 December 31, 23h 59m 59s 2008 December 31, 23h 59m 60s 2009 January 1, 0h 0m 0s The difference between UTC and the International Atomic Time TAI is: from 2006 January 1, 0h UTC, to 2009 January 1 0h UTC : UTC-TAI = - 33s from 2009 January 1, 0h UTC, until further notice : UTC-TAI = - 34s 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 is 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 Head Earth Orientation Center of IERS Observatoire de Paris, France