Re: [LEAPSECS] Longer leap second notice

From: Poul-Henning Kamp <>
Date: Wed, 04 Jan 2006 21:31:22 +0100

In message <B657485C-A8E9-42DE-A6A5-0AAFAB407189_at_NOAO.EDU>, Rob Seaman writes:
>Hi Warner,
>> A more apt comparison would be to the leap year rules that we
>> have. We know the rules going
>> forward a thousand years or so.
>Apt indeed. Leap seconds are scheduled at least six months in
>advance. That's about one part in 15 million. A thousand year
>horizon for scheduling leap days is one part in 365,250. So we're
>already doing 50 times better than Julius Caesar and Gregory XIII.

This comparison is utter rubbish, and you know it.

>Little support - and again, to a certain level of precision (easily
>better than a second per day), all parties must certainly agree that
>civil time (as we know it) IS mean solar time.

Since you keep repeating this "Nixon cannot have won, nobody I know
voted for him" falsehood let me express myself in very simple terms:

    No, I do *NOT* agree that civil time is mean solar time.

Got it ?

Civil time is at best local solar time +/- up to several hours in
either direction depending who you are and where you are.

Seveal geographical/political regions have actively chosen to
increase the distance between mean solar time and local time during
various stretches of time, often in periodic fasion and sometimes
with far too little thought before the decision.

We keep hearing "use an appropriate timescale" and in the same emails
we hear "UTC is a convenient approximation of UT1".

Sounds to me like that argument should be backfired: If you need UT1,
then use an appropriate timescale: UT1, don't force the majority
of UTC users to suffer because you use the wrong timescale.

>Can't argue with that - although ultimately a single well tied knot
>is stronger than a tangle of slip knots and Grannies.

We're not talking about knots here, this is not cryptography,
we are talking about byzantine decision scenarios (I have three
references, one say leap second, one says no leap second and one
says nothing, what should I do ?)

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk_at_FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Received on Wed Jan 04 2006 - 12:42:29 PST

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