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Dear
Project Manager or Scientist,
It is being proposed to change the
definition of Coordinated Universal
Time (UTC) regarding the insertion
of leap-seconds, possibly even
eliminating their use. Leap
seconds are introduced so as to keep UTC
synchronized (within 0.9 s) to
the time scale determined from the
Earth's rotation, however many
practical problems result from
their
implementation.
Should no new leap seconds be
inserted, solar time will diverge from
atomic time at the rate of about
2 seconds every 3 years, and after
about a century |UT1-UTC| would
exceed 1 minute. Although no
fundamental problems are
anticipated, it is very likely that Y2K-like
problems may result in
software that assumes UT1=UTC, or |UT1-UTC|< some
value, or whose
input/output records use a field size that can only
accommodate
|UT1-UTC| values up to one second.
To gather information, an URSI
Commission J Working Group was formed,
consisting of Don Backer, Wim.
N. Brouw, Barry Clark, Irwin Shapiro,
Ir. E. Van Lil, and
myself.
We would like to ask you to consult with the members of
your institute
who currently deal with UT1-UTC, and give us a
considered response to
the following two questions:
A. If
the appropriate international bodies decide to eliminate the
insertion
of new leap seconds, would you foresee any practical problems
for your
institution/instrument/observations?
no
____
* yes ___
* possibly
____
(* please explain any known or possible
problems)
B. Would you be in favor of such a
proposal?
yes
____
no
____
indifferent
___
have better idea
___
(feel free to comment)
C. Is
there anyone else you would recommend we contact?
(feel
free to forward this eamil directly)
I would appreciate your
assistance, and a response by January 15 to
dnm@orion.usno.navy.mil.
[snip]
Sincerely,
Demetrios
Matsakis
________________________________________________________________________
Dr.
Demetrios N.
Matsakis
Director, Time Service Department
(202) 762-1587 DSN
762-1587 U. S. Naval
Observatory
FAX (202)
762-1511
3450 Massachusetts Avenue NW
dnm@orion.usno.navy.mil
Washington DC, USA
20392-5420
________________________________________________________________________