[LEAPSECS] a modest proposal

Poul-Henning Kamp phk at phk.freebsd.dk
Sun Feb 10 18:04:52 EST 2008

In message <968AC643-450C-405C-AAD3-3FBF79AA7027 at noao.edu>, Rob Seaman writes:

>Maybe you won't have to muck about with computers - but large expanses

>of astronomical infrastructure will have to be refactored by others.

I think we have been over this ground before.

Last I checked, computers with an awareness of H:M:S time outnumber
astronomical instruments 100.000 to 1, likely more.

>Each missed leap second is 15 arcseconds on the celestial equator -

>many time the precision required to point a telescope.

This is where I fail to see the magnitude of the problem you

It obviously follows, that with leap second granularity of 1 SI
second, you need to keep track of the residual also, so your telescope
already uses (UTC + DUT1), effectively UT1, for pointing, right ?

So all that you will suffer, is that DUT1 is not guaranteed to be
numerically less than plus/minus one.

I seriously doubt that is going to be a major catastrophic problem
for astronomy.

But I'll grant you that some astronomy tools will need fixing, but
they are outnumbered at least 100.000:1 by computers that just won't
care or need to care.

Add on top of that, that the majority of the 100.000 computers are
under the control of morons, and the one computer in astronomy is
not to be touch by anybody less than a graduate student, and the
relative trouble of fixing things gets even more skewed in astronomys

Yes, it's unfair, but astronomy is outnumbered and without the
former clout of owning the navigational aids, I can't see much
you guys can do about it...

That's why I think what you should do, is play cooperative, and
try to get as much money and new instruments out of it as you can,
while you can.

>Which is it? Either the cessation of leap seconds is a complex

>question that demands a well thought out plan - or the cessation of

>leap seconds is a simple question for which a plan would be trivial to

>generate at the level of nuance required. Either way, is it too much

>to expect that an actual plan be written?

I would expect, that the plan may be written down on the back
of a napkin somewhere, having the following substance:

1. Ratify changed document.

2. Announce changed document.

3. Mail copy to BIPM.

4. Case closed -- not our problem any more.

That is a large part of the attractiveness of just dropping


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.

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