[time-nuts] On Setting the Astronomical Time

Magnus Danielson magnus at rubidium.dyndns.org
Sun Jun 10 15:48:30 EDT 2007

From: "Tom Van Baak" <tvb at LeapSecond.com>
Subject: Re: [time-nuts] On Setting the Astronomical Time
Date: Sun, 10 Jun 2007 12:35:49 -0700
Message-ID: <001501c7ab96$8d1e5d50$0300a8c0 at pc52>

> > Setting your clock using GPS time, or with the known offset UTC is straight 
> > forward.  Offsetting UTC using the posted value of DUT1 gets you UTC1 good to 
> > 0.1 seconds.  But that's 8 orders of magnitude away from the precision of UTC.
> Correct. See plots of earth accuracy and stability:
> http://www.leapsecond.com/museum/earth/
> > Is there some way to get TT to better than a tenth of a second, or is the earth 
> > just too sloppy of a time keeper?
> Don't know for sure but the following may help you:
> http://maia.usno.navy.mil/
> http://www.iers.org/MainDisp.csl?pid=36-9
> http://maia.usno.navy.mil/ser7/finals.daily
> http://maia.usno.navy.mil/search/search.html
> My recollection is that using VLBI, UT1 is measured to
> sub-millisecond even microsecond levels.
> For example, yesterday UT1-UTC was -148.709 ms, today
> it is -149.996 ms, and tomorrow it will be -151.172 ms.

Don't you get the IERS emails? Sign up and get them each month. Such a joy
reading the latest statistics on how the rock jittered.


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