Hi Tom:
One of my interests is in Sun dials, so I like the idea of civil time corresponding as close as possible to the Sun's
position. Heliochronometers can be accurate to some seconds.
The Dent <http://www.prc68.com/I/Dent.shtml>Dipleidoscope <http://www.prc68.com/I/Dent.shtml> was used to set railroad
clocks based on the Sun's position.
Another area of interest is astronomy where UTC1 adds a correction to a tenth of a second to UTC that essentially
bridges the gap between the leap second corrections.
It would be interesting to learn how the Software Bisque Paramount telescope mount handles time. It does not have any
provision for a time nuts oscillator/clock, but maybe should?
--
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.
-------- Original Message --------
If UTC time was adjusted every month would stick with one full second? Or
some smaller quantity?
Hi Scott,
The LSEM month suggestion retains the UTC policy of leaps being exactly +1 or
-1 second, never larger, never smaller.
There's a world of hurt if anyone even dreamed of shifting UTC by a fraction of
a second. In fact, one of the main reasons UTC was created in the 70's was to
put an end to the dreaded fractional jumps in atomic timekeeping during that
era. Fractional steps atomic frequency and fractional steps in atomic time were
both tried during 60's. For example:
http://www.leapsecond.com/history/wwvb1966.htm
Eliminating frequency jumps completely (by defining the UTC second to be
9,192,631,770 Hz cesium), and
changing any steps to be full +1 or -1 second integers (and not fractions) was
why UTC was created.
/tvb
----- Original Message -----
From: "Scott Stobbe" <[email protected]>
To: "Discussion of precise time and frequency measurement" <[email protected]>
Sent: Thursday, July 21, 2016 3:06 PM
Subject: Re: [time-nuts] LSEM (Leap Second Every Month)
If UTC time was adjusted every month would stick with one full second? Or
some smaller quantity?
On Thursday, 21 July 2016, Brooke Clarke <[email protected]> wrote:
Hi Tom:
I like this idea. I addresses the lesson from Y2K that something done
often works much better than something done only occasionally.
That's way you see the firetruck at the local store, because it's used all
the time and so is more likely to work when needed.
--
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.
-------- Original Message --------
Hi Tom...
Does your proposal allow for a Zero leap second, or does it require
either plus or minus 1 to work? Seems like you could stay closer to the
true value if you also have a zero option. Might also cause less
consternation for some services, like the finance and scientific worlds,
that seem to have critical issues when an LS appears.
I like your point that by having it occur monthly it forces systems to
address issues promptly, and maybe that's the argument for the non-zero
option.
Tom Holmes, N8ZM
-----Original Message-----
From: time-nuts [mailto:[email protected]] On Behalf Of Tom Van
Baak
Sent: Thursday, July 21, 2016 1:28 PM
To: Discussion of precise time and frequency measurement <
[email protected]>
Cc: Leap Second Discussion List <[email protected]>
Subject: Re: [time-nuts] Leap second to be introduced at midnight UTC
December 31 this year
Time to mention this again...
If we adopted the LSEM (Leap Second Every Month) model then none of this
would be a problem. The idea is not to decide *if* there will be leap
second, but to force every month to have a leap second. The IERS decision
is then what the *sign* of the leap second should be this month.
Note this would keep |DUT1| < 1 s as now. UT1 would stay in sync with
UTC, not so much by rare steps but by dithering. There would be no change
to UTC or timing infrastructure because the definition of UTC already
allows for positive or negative leap seconds in any given month.
Every UTC-aware device would 1) know how to reliably insert or delete a
leap second, because bugs would be found by developers within a month or
two, not by end-users years or decades in the future, and 2) every
UTC-aware device would have an often tested direct or indirect path to IERS
to know what the sign of the leap second will be for the current month.
The leap second would then become a normal part of UTC, a regular monthly
event, instead of a rare, newsworthy exception. None of the weird bugs we
continue to see year after year in leap second handling by NTP and OS's and
GPS receiver firmware would occur.
Historical leap second tables would consist of little more than 12 bits
per year.
Moreover, in the next decade or two or three, if we slide into an era
where average earth rotation slows from 86400.1 to 86400.0 to 86399.9
seconds a day, there will be zero impact if LSEM is already in place.
/tvb
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