"Richard B. Gilbert" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Daniel Norton wrote:
>
> > Why does USNO show several seconds faster than time.gov (and other
> > references)?
> >
>
> It is not, now, off by "several seconds".  I'm inclined to doubt that it
> ever was!   I think you are misinterpreting something.  Perhaps you are
> reading milliseconds as seconds?
>
He's not misinterpreting anything.  The animated clocks and the static
display have indeed been several seconds fast lately as compared to
time.gov, WWV, etc.  (I haven't checked lately; they may have fixed it by
now.)
I just assumed this was due to their having deprecated these older Web-based
services in favor of the time.gov site, which is a joint project with NIST.

>  From here, tick.usno.navy.mil is within 898 microseconds of my own
> stratum 1 (GPS reference clock) server which is amazingly good.  Usually
> internet servers are off by anywhere from two to ten milliseconds!  Note
> that the servers themselves are within a few microseconds or even a few
> nanoseconds of the correct time but asymmetric network delays usually
> introduce an offset of several milliseconds.
>
> FWIW, the "offset" in the ntpq -p banner is in milliseconds!

I've no doubt that USNO is spot-on to at least ten decimal places
internally, but once their internet-based time transmissions leave
Washington they're subject to getting stuck in traffic, running out of gas
and carjacking just like the rest of us.


Brian Garrett


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