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Re: Leap seconds
From: Greg R_
Date: 2009 Jan 11, 11:33 -0800
From: Greg R_
Date: 2009 Jan 11, 11:33 -0800
No need for George to get snippy either, though he has a history of doing that and then complaining whenever someone calls him on it. -- GregR --- On Sun, 1/11/09, Fred Hebardwrote: > From: Fred Hebard > Subject: [NavList 6981] Re: Leap seconds > To: NavList@fer3.com > Date: Sunday, January 11, 2009, 10:02 AM > No need for this Greg. > > On Jan 11, 2009, at 12:23 PM, Greg R. wrote: > > > > > 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@hux.me.uk > >> or at +44 1865 820222 (from UK, 01865 820222) > >> or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 > 5HX, UK. > >> > >> > >> > >> > >> > >> > > > > > > > > > > --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---