[LEAPSECS] the big artillery
Joseph M Gwinn
gwinn at raytheon.com
Tue Nov 4 16:20:55 EST 2014
"LEAPSECS" <leapsecs-bounces at leapsecond.com> wrote on 11/04/2014 02:45:09
> From: Brooks Harris <brooks at edlmax.com>
> To: leapsecs at leapsecond.com
> Date: 11/04/2014 02:45 PM
> Subject: Re: [LEAPSECS] the big artillery
> Sent by: "LEAPSECS" <leapsecs-bounces at leapsecond.com>
> On 2014-11-04 11:53 AM, Gerard Ashton wrote:
> > Of course Brooks Harris is free to define proleptic UTC any way he
> > within the confines of a document he has control over, including a post
> > this mailing list. But I think the term "proleptic UTC", outside the
> > confines of a document that gives it a proprietary definition, could
> > variety of things.
> Sure, thanks. But using a name that elicits incoming projectiles isn't
> so helpful either. I'll conjugate on, or accept suggestions for, a
> better name.
> > For example, the Standards of Fundamental Astronomy
> > subroutine iauDat provides the delta between TAI and UTC, and the
> > code comments say "UTC began at 1960 January 1.0 (JD 2436934.5) and it
> > improper to call the function with an earlier date."
> For purposes of astronomy, and probably others, the "rubber band era"
> may have relevance. To call it "UTC" seems a bit of a stretch to me, but
> there's no generally accepted name for what Zefram calls "rubber-seconds
> era of UTC". Everybody has seized the name, and attempted to give it
> some meaning other than what I, at least, consider to be its origin -
> 1972-01-01T00:00:00Z, when there was exactly 10 seconds initial TAI-UTC
> offset, and when Leap Seconds were deemed to exist. As we've heard so
> often here, the term doesn't appear until sometime late in the
> development of the timescale. POSIX seized on it, NTP, PTP, and here
> another organization has extrapolated it into the past.
POSIX originally cited GMT, and changed to UTC around 1988, the reason
being simply that NIST (NBS then) had gone to UTC.
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