[LEAPSECS] Straw men

Ian Batten igb at batten.eu.org
Mon Jan 9 14:40:15 EST 2012

On 9 Jan 2012, at 1845, Rob Seaman wrote:

> Ian Batten wrote:


>> And you accuse others of erecting straw men? Are you saying that if UTC were redefined tomorrow, in a hundred years time there would still be equipment in use that would be mis-behaving?


> Convenient way to forget the word "decades". Yes, I expect issues to continue to arise decades hence in currently deployed systems and processes. There are, for instance, ongoing Y2K-related issues.

[Citation Needed]

> And since time-of-day will fundamentally remain mean solar time,

[Citation Needed]

> issues due to confusion will continue to arise indefinitely in new code, new systems, new "equipment".

The set of equipment that needs any time other than civil time is vanishingly small. If you need it directly, you have a national LF service. If you need it slightly less directly, you have a GPS receiver and know what the offset is. And if you're normal, NTP will do the job just fine. So long as those all tick the same thing, its relationship to the rotation of the earth is, +/- several hours, irrelevant. No-one cares what the relationship between their watch/clock/computer and the sun is at anything other than the grossest scale, and attempting to claim unhitching UTC from UT1 will have any practical effect is only frightening to people who still don't realise that Penzance is 20 minutes adrift from London. It's different for astronomers. The question is, should the rest of us be obligated to use a time scale which causes us difficulties which we could fix easily were it not for the needs of a small scientific community?


>> We get that you say you've got instruments that rely on a steady diet of UTC which either assume that DUT1 is negligible for the purpose at hand (in which case it's not clear why |DUT1|<0.9s is fine while |DUT1|<1.1s is the end of the world),


> Were you paying attention to Y2K?

Indeed, I got six months' salary as a bonus for my contribution to sailing it through it without a single issue in my employer's business. What were you doing for Y2K? You do realise that "The astronomical community started preparing for Y2K in 1996 and barely had enough time" isn't something to be proud of, don't you? We'd _finished_ by 1996, having started the programme in about 1989. So a little less of the "the astronomical community are the only competent engineers, the rest of you are just charlatans" would be nice.

> nd for the thousandth time, correcting an error offset at some future time is not the only issue here. The rate will mismatched to Earth rotation at all epochs in between.

When was the _rate_ of UTC such that 86400s == 1 mean solar day?


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