[LEAPSECS] DUT1 about to backtrack

John Sauter John_Sauter at systemeyescomputerstore.com
Sat Jan 9 04:38:23 EST 2021


On Fri, 2021-01-08 at 22:51 +0000, Michael Deckers wrote:
> 
> On 2021-01-08 19:57, John Sauter via LEAPSECS wrote:
> 
> > I attach a plot of historical values of DUT1 based on the old
> > issues of
> > Bulletin A kept on the IERS' web site.
> 
> 
> 
>     I think the graph of DUT1 is not quite correct, for instance:
> 
>     On 2009-01-01, there was a switch of DUT1 from -0.6 s to +0.4 s
> due 
> to a leap second (Bulletin C36)
>     On 2009-03-12, there was a switch of DUT1 from +0.4 s to +0.3 s 
> (Bulletin D102)
>     Your graph only has one switch, on 2009-01-01 from -0.6 s to +0.3
> s
> 
>     Michael Deckers.
> 
I was getting the DUT1 values from Bulletin A, but as you point out
that is not very accurate.  I tried to use Bulletin D, but it omits the
change in DUT1 caused by a leap second.  To get an accurate chart I
will have to combine the information in Bulletin D with a table of leap
seconds.

Here is the chart based only on Bulletin D.  It shows that the current
interval of no change in DUT1 is the longest since 1991.
    John Sauter (John_Sauter at systemeyescomputerstore.com)

-- 
get my PGP public key with gpg --locate-external-keys
John_Sauter at systemeyescomputerstore.com

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