[fitsbits] Future of UTC

[Rob Seaman]

Clive Page writes:

> We try to educate all the software developers and users as to the
> difference between TAI and UTC, and try to get TAI used exclusively
> in the data analysis chain.

Sounds like the proper solution - too bad the logic is undermined
by the next three statements:

> Unfortunately ground stations invariably use UTC, and
> have to insert leap seconds manually.
> The astronomer has little control over this process,

1) If ground stations use UTC, perhaps there are good reasons for this?
   The problem isn't that they use UTC for their own purposes, it's that
   they don't support alternate time systems for client spacecraft.
2) Just because ground stations use UTC doesn't mean that processes
   can't be used to automatically adjust for leap seconds.
3) If astronomers have no control over the current process, why should
   we assume they will have any more control over whatever process is
   substituted?

The problem is not the definition of civil time standards (which
should continue to rely on UTC approximating GMT).  The problem is
that professionals in astronomy and elsewhere treat their clocks with
a lack of care that would be shocking for any other standards of
measurement.

If an unsegmented timescale like TAI is what you need - TAI is what you
should use, and the implications of your project design should be made
clear to management.  The fix for aging and broken ground stations is
not to redefine civil time for the entire planet for all time.

> In summary: my opinion is that many astronomers using space-based
> observatories will welcome the abandonment of leap seconds.

To date, only such anecdotal evidence has been offered.  The "surveys"
have been laughable and the "process" is embarrassing.  It is far from
obvious that the organizers of the Torino workshop even have standing
to make such a radical change to the UTC standard.  There appears to
be great pressure to act quickly - from a shadowy faction with a hidden
agenda - when we literally have hundreds of years to make up our minds.

A revision to such a central standard as UTC deserves much more care in
design and implementation.  All interested parties (literally everyone
on the planet) should have the opportunity to comment.

Rob Seaman
National Optical Astronomy Observatory