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        Gazette IERS Gazette IERS Gazette IERS Gazette IERS Gazette
                                    _______________________________________
        No 16, 04 April 1997       /
__________________________________/                 Contact: iers@obspm.fr
                                     ftp:  hpiers.obspm.fr (145.238.100.28)
                              WWW:  http://hpiers.obspm.fr
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	                ------------------------------
                         ERRATUM to IERS Gazette No 8
                        ------------------------------
                                                
                  REVISION OF IERS EOP SERIES ON 1 JANUARY 1997                                                        
	
	There was a sign error in the periodic correction to be applied on
UT1-UTC starting with 1 January 1997, as given in IERS Gazette No 8 (29.10.96).
The GST formula in IERS Conventions (1996), IERS T.N. No 21 (p. 21) is 
confirmed. The values of the changes of biases and drifts for all EOP are 
also confirmed.

	We thank the colleagues who pointed out the mistake and we apologize 
for any inconvenience caused.
	
	The correct formula for the change in UT1-UTC is as follows.        
 ____________________________________________________________________________
|                                                                            |
| Correction to IERS UT1 series on 1 Jan 1997 (MJD=50449.0)       Units      |
|____________________________________________________________________________|
|                                                                            |
|   UT1_new - UT1_old = - 0.2 + 0.03*(T-50449.0)/365.2422         0.0001s    |
|                       - 1.76 sin(Omega) - 0.04 sin(2.*Omega)    0.0001s    |
|                       ^                 ^                                  |
| Where                                                                      |
|        - T is the date in Modified Julian Days (MJD)                       |
|        - Omega = mean longitude of the ascending node of the Moon          |
|                = 125.04 deg - 0.052954 deg*(T-51544.5)                     |
|----------------------------------------------------------------------------|
|   THE FIRST LINE (BIAS AND DRIFT) IS AS GIVEN IERS GAZETTE No 8            |
|   THE SECOND LINE HAS A CHANGE OF SIGN WITH RESPECT TO IERS GAZETTE No 8   |
|____________________________________________________________________________|

        The error made in January-March 1997 is smaller than the estimated 
precision of Bulletins A and B. Bulletin B for March 1997 will have the correct 
correction. The IERS EOP series recomputed in the new system and available via 
www and ftp are already modified.


Contacts:  Bulletin A: dmc@maia.usno.navy.mil
           Bulletin B, EOP 97 C 01,02,03,04: gambis@obspm.fr