[time-nuts] NIST UT1 NTP server results

[Tom Van Baak]

> If this turns into a serious thing then it deserves consideration
> whether such servers should be UT1, or instead UT2.


Hi Steve,

I've always been curious about the conflict between accuracy and stability with these various time scales.

If the purpose of a UTx clock is long-term timekeeping, then I can see that smoothing is helpful. OTOH, if the purpose of a UTx clock is to pinpoint a telescope, then smoothing is exactly what you don't want. That is, what you want is to know where to point the telescope right now, not the average of where you would have pointed the telescope each day over the past year. The former is a precise actionable measurement; the latter is a filtered historical statistic.

Can you shed light on this? Who / how / why was UT0 vs. UT1 vs. UT2 used in practice?

Thanks,
/tvb

----- Original Message ----- 
From: "Steve Allen" <sla at ucolick.org>
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Sent: Saturday, July 23, 2016 8:52 AM
Subject: Re: [time-nuts] NIST UT1 NTP server results


> On Sat 2016-07-23T10:10:07 -0400, Bob Camp hath writ:
>> Ok, so now what we need are at least 5 other public UT1 NTP servers so you can properly
>> synch up to a set of them.
> 
> If this turns into a serious thing then it deserves consideration
> whether such servers should be UT1, or instead UT2.
> 
> UT2 was the standard in the CCIR recommendations for radio broadcasts
> before UTC with leap seconds (and in fact it was specified as the
> underlying time scale in the first version of the CCIR leap second
> document) specifically because it was smoother than UT1 over the
> course of a year.
> 
> --
> Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
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>