[LEAPSECS] Notation for transmitted vs. paper time scales

Greg Hennessy greg.hennessy at cox.net
Wed Nov 5 19:48:10 EST 2014


> Paper time-scales only exist because we couldn't do any better when
> we had to wait for the astronomers to mail a letter to Paris with
> their observations.
>
> Today with realtime global clock comparisons available, both GPS
> phase and point-to-point via sat/fiber, the only contribution in
> the "paper" version provides, is that it allows us to use a non-causal
> weighing algorithm (ie: one which reduces a clocks weight earlier
> in time for something it did later.)
>
> For all practical purposes we could dismiss with paper clocks
> and go real time, but I'm sure astronomers will tell us that
> would do things to the cows milk or something...

I'd hate to get in Poul's slandering of astronomers, but if
you are trying to measure UT1, it still takes time to correlate
the VLBI data and reduce it, and then send the results
to the right people, which doesn't happen without delay. (pardon
the pun). Synching up cesiums, hydrogen masers, and rubidium
fountains can happen much faster than it used to of course.





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