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    Re: Leap seconds
    From: Greg R_
    Date: 2009 Jan 11, 09:23 -0800

    Ignoring his usual pomposity (not to mention the unnecessary verbosity and 
    prolixity in this post), I take it that George agrees substantially with what 
    I originally posted (at least in principle, if not necessarily with my 
    particular choice of words).
    
    So thanks for finally agreeing with me, George - if only in your usual oblique 
    (and occasionally obtuse) manner. That wasn't so hard, was it?
    
    --
    GregR
    
    
    
    --- On Sat, 1/10/09, George Huxtable  wrote:
    
    > From: George Huxtable 
    > Subject: [NavList 6976] Re: Leap seconds
    > To: NavList@fer3.com
    > Date: Saturday, January 10, 2009, 3:52 PM
    > Referring, apparently,  to posting [6933] (with which I have
    > no
    > disagreement) from Gary LaPook, GregR has written-
    >
    >
    > "George:
    >
    > Are you reading this? Because this is EXACTLY what I was
    > referring to
    > earlier (i.e. that whatever time scale we use as navigators
    > is totally
    > irrelevant - as long as we can correlate it to the time in
    > an almanac, or
    > whatever is used to obtain the date/time for a celestial
    > event).
    >
    > I still don't know if you were being troll-ish earlier
    > or honestly trying to
    > contribute to the discussion, but at least I'm not the
    > only one who
    > understands the concept - however abstract it might be for
    > some on the list
    > to comprehend."
    >
    > =============================
    >
    > Coming from anyone else on this list, I would simply laugh
    > off the personal
    > comments in that posting, but GregR has a track record of
    > repeated and
    > unwarranted personal unpleasantness in some of his earlier
    > contributions, so
    > I am disinclined to treat such matters lightly, from him.
    >
    > If he can avoid getting overheated, and deal with any
    > question on a straight
    > factual basis, as I will do, we may be able to manage
    > fruitful discussion
    > between us. Otherwise, not.
    >
    > ============================
    >
    > To be honest, I'm not really sure what Greg is arguing
    > about. He contends
    > "that whatever time scale we use as navigators is
    > totally irrelevant - as
    > long as we can correlate it to the time in an almanac, or
    > whatever is used
    > to obtain the date/time for a celestial event"
    >
    > I might well agree, depending on what meaning we agree on
    > for "correlate".
    > If that includes adjusting for the number of leap seconds
    > that would have
    > occurred since the almanac was produced, which is what
    > would need to happen
    > if we adopted Atomic Time for our clocks, then GregR and I
    > do not differ.
    >
    > I don't know how long in advance almanacs are
    > calculated and printed, but
    > let's say, for the purpose of argument, five years. So
    > that means that the
    > almanacs that we use today were produced in 2004. There was
    > no way the
    > compilers could predict, then, just how much the Earth
    > would slow in the
    > next 5 years. If we were to switch to Atomic Time, it would
    > mean that before
    > we could use any of the data in an almanac, we would need
    > to discover how
    > much the Earth's spin had diverged from its nominal
    > rate in that interval,
    > and allow for it by adjusting the reading of an accurate
    > clock. That applies
    > to predictions, not just of the Sun, but of any planet, and
    > via GHA Aries,
    > any star. Each one of us, individually, would have to work
    > out our own
    > correction, depending on the date of our almanac and the
    > (unpredictable)
    > adjustment that's called for. Instead of what happens
    > now, when it's done
    > automatically (within less than a second of error, anyway)
    > for us all, by
    > applying leap-seconds to everyone's clock.
    >
    > It's a matter of discussion whether Atomic Time or the
    > present compromise of
    > Leap-second-adjusted time is the most convenient way to
    > work our clocks in
    > the future. My personal opinion is that neither is, but a
    > smoothly adjusted
    > clock-rate, that corresponds as well as possible to the
    > observed rotation of
    > the Earth, would be more viable over the long run. But that
    > isn't relevant
    > to our present discussion.
    >
    > Let's take the chance, now, to clear up some loose ends
    > from GregR's initial
    > posting, [6805]. He had written "Besides, the almanacs
    > have been on UT since
    > when - mid 70s? (and thus pretty much
    > "disconnected" from "sun time")."
    > On
    > the contrary, we have seen that almanacs are, indeed,
    > closely connected with
    > Sun Time, because UT is, within less than a second, by the
    > operation of leap
    > seconds. And I have asked him what it is that he reckons
    > occurred in the
    > mid-70s to change that situation, to which there has been
    > no reply.
    >
    > George.
    >
    > contact George Huxtable, at  george{at}hux.me.uk
    > or at +44 1865 820222 (from UK, 01865 820222)
    > or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    >
    >
    >
    >
    >
    >
    
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