On 4 Aug 2011, at 16:10, Warner Losh wrote:
>
> The error grows with DUT1, so using UTC to navigate, point telescopes, etc
> becomes harder. Systems that used to ignore DUT1 errors since they were
> small would need to be updated. Other than navigation by sextant though, I'm
> not aware of too many things that are DUT1 sensitive that don't get DUT1 from
> somewhere.
Taking a sight with a sextant involves recording the time at the precise moment
the sight was taken. That's going to be +/- 1s at best, owing to the
resolution of the timing device, and that in turn is going to be +/- 1s owing
to the UTC/UT1 delta. So sextant navigation is already coping with +/- 2s.
Wikipedia (yeah, I know) says that navigation to +/- 1nm is good going.
Circumference of the earth is 21600nm, so 1nm is (presumably, I'm guessing
here) equivalent to 4s. It sounds to me like publishing DUT1 on an annual
basis would be more than good enough, and people who do sextant navigation
would just know to set their watches accordingly. It could be broadcast as
part of the shipping forecast.
ian
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