[LEAPSECS] LEAPSECS Digest, Vol 45, Issue 1

Rob Seaman seaman at noao.edu
Fri Sep 3 00:50:57 EDT 2010


Tony Finch wrote:


>>> The fact that it used to be a mean solar timescale is now just etymology.

>>


I wrote:


>> I know it to be untrue for systems under my oversight.


Tony wrote:


> No. You do not run any systems synced to solar GMT. No-one does.


Perhaps I elided too much context. Tony said:


>>> The alternative argument is that GMT (the astronomical timescale) has not been maintained for decades, and all current solar timescales have different more specific names. All official time sources (legal time) in the UK have been synced to UTC for decades. For all practical purposes what we call GMT (the only current use for the term) is now de facto the same as UTC. The fact that it used to be a mean solar timescale is now just etymology.


I was referring to GMT broadly as "the astronomical timescale" and "for all practical purposes" "de facto the same as UTC". I believe Tony is talking narrowly about the official "Greenwich Mean Time", more like http://bit.ly/cWcznJ, although it is pretty clear that the public remains very much "synced" to GMT, eg, http://bit.ly/aHWJYw

Rob


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