[LEAPSECS] Question about UT1 and the IERS Reference Meridian

Dennis Ferguson dennis.c.ferguson at gmail.com
Thu Apr 30 00:03:09 EDT 2015

On 29 Apr, 2015, at 18:01 , Mike Lawson <mflawson2 at cox.net> wrote:
> So, what I take from this is, 1) UT1 (and hence UTC) is based on the International Reference Meridian, not the Prime Meridian (Greenwich).  2)  “True” GMT (if the mean sun can accurately be measured and predicted by formulae, which has its own set of problems and error bars) lags UT1 by about 0.36 seconds; but it doesn’t really matter, since the whole world is now based on the IRM.

That's correct except that I don't think the 0.36 seconds is
seconds of time, it is angular seconds.  That would be a
24 millisecond time difference.

Dennis Ferguson

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