Gerard Ashton wrote: >The westernmost point of the London Borough of Greenwich
Irrelevant. The names "Greenwich Mean Time" and "Greenwich meridian" don't refer to the borough per se, but specifically to the transit instrument at the Royal Observatory, Greenwich. (Historically there were two meridians so defined, from different transit instruments at the observatory.) The historically-authentic Greenwich meridian is well defined to a precision of a centimetre or so on the ground at Greenwich (600 microarcseconds, or 40 microseconds of angular time). There's no qualitative difference between being 5 seconds off GMT and being 6 seconds off GMT. Side note: wow, IERS's claimed 6 us error on UT1-UTC (in Bulletin A) corresponds to only 3 mm at the equator. Even more impressive than the errors on pole location, which are also about 3 mm on the ground (at the pole). -zefram _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
