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frankreed@HistoricalAtlas.net wrote:
> And Lu wrote:
> "And that last sentence is the key to your question of "how would I
> practice celestial navigation if we didn't have leap seconds"   As long
> as I could convert my local time into Almanac time, it wouldn't matter,
> just as I adjust from local time to GMT."
>
> So you also agree that it would be no issue, right? The author of the time
> article suggested that the "vanishing breed" of celestial navigators would
> be upset over the abolition of leap seconds. I think that's incorrect.
Oh, I absolutely agree it would be no issue.  As I said in my original
post, there's a difference between the passage of time (as measured,
say, by an atomic clock) and answering the question "what time is it?"
If we lived in a world without leap seconds, our chronometers would show
leap-second-less time and the almanac would show the positions of
celestial bodies in leap-second-less time.  As long as we all agree on
how to answer the question "what time is it," it really doesn't matter
exactly how we do it.  An extreme example would be to suddenly start
keeping metric time - metric watches and metric almanacs, what's the big
deal?
> We
> would have little problem adjusting the rules in a world without
> leapseconds. But I'm still interested in some of the options as to how this
> might be done. Suppose I publish a nautical almanac today for the year 2058.
> How could I use it correctly for celestial navigation in that year? Adjust
> the input time??
Publishing a Nautical Almanac today for 2058 would face the issue of
trying to predict how many leap-seconds would be inserted into UTC in
the next 50 years.   I can predict the location of the celestial bodies
quite well, but I can't predict whether UTC will be different from
today's time by three or five or 10 seconds.   Maybe would I need to add
another line to my time calculations in my sight reduction forms; in
addition to Watch Error and ZD, I need a line for "leap second
corrections."   Either that or the government publishes 50 years worth
of Nautical Almanacs at once ("we got a good price on a big order") and
therefore declares the end of leap-seconds so as to not obsolete this
huge inventory :-P .

Lu


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