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Physical Measurement Laboratory / Time and Frequency Division

Time Realization and Distribution Group

NIST USNO 2004 Archive

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UTC(USNO) - UTC(NIST)

The United States Naval Observatory (USNO) and the National Institute of Standards and Technology (NIST) make regular comparisons of their respective time scales. These comparisons are made using GPS common-view measurements from up to approximately 10 GPS satellites. The table below lists recent differences between the two time scales.

Weekly UTC(USNO, Master Clock) - UTC(NIST)Values

Date MJD

UTC(USNO)-UTC(NIST) (+/- 20 nanoseconds)
2004-12-30   53369 10 ns
2004-12-23   53362 13 ns
2004-12-16   53355 13 ns
2004-12-09   53348 14 ns
2004-12-02   53341 16 ns
2004-11-25   53334 14 ns
2004-11-18   53327 13 ns
2004-11-11   53320 11 ns
2004-11-04   53313 10 ns
2004-10-28   53306 10 ns
2004-10-21   53299 11 ns
2004-10-14   53292 12 ns
2004-10-07   53285 11 ns
2004-09-30   53278 11 ns
2004-09-23   53271 11 ns
2004-09-16   53264 13 ns
2004-09-09   53257 11 ns
2004-09-02   53250 7 ns
2004-08-26   53243 6 ns
2004-08-19   53236 4 ns
2004-08-12   53229 3 ns
2004-08-05   53222 -1 ns
2004-07-29   53215 0 ns
2004-07-22   53208 -3 ns
2004-07-15   53201 -2 ns
2004-07-08   53194 -1 ns
2004-07-01   53187 -1 ns
2004-06-24   53180 -1 ns
2004-06-17   53173 0 ns
2004-06-10   53166 3 ns
2004-06-03   53159 7 ns
2004-05-27   53152 9 ns
2004-05-20   53145 13 ns
2004-05-13   53138 17 ns
2004-05-06   53131 17 ns
2004-04-29   53124 18 ns
2004-04-22   53117 17 ns
 
2004-04-15     53110 14 ns
 
2004-04-08   53103 10 ns
 
2004-04-01   53096 4 ns
 
2004-03-25   53089 1 ns
 
2004-03-18   53082 -1 ns
 
2004-03-11   53075 -2 ns
 
2004-03-04   53068 -6 ns
 
2004-02-26   53061 -12 ns
2004-02-19   53054 -15 ns
2004-02-12   53047 -11 ns
2004-02-05   53040 -17 ns
2004-01-29   53033 -21 ns
2004-01-22   53026 -22 ns
2004-01-15   53019 -24 ns
2004-01-08   53012 -21 ns
2004-01-01   53005 -19 ns
Time and frequency
Created January 13, 2010, Updated October 7, 2020
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