Timesys note review
msdemlei at ari.uni-heidelberg.de
Tue Dec 4 09:52:31 CET 2018
Hi Steve, Hi Apps,
On Thu, Nov 29, 2018 at 10:30:51AM -0800, Steve Allen wrote:
> As Rob Seaman reiterates, very few observations have timestamps that
> merit the distinction between UT1 and UT. UT1 implies that some
> special care has been taken in post-observation data reduction. There
> are no tabulations with self-consistent re-reductions of the
> difference between UT1 and the available time signals from before the
> change from FK3 catalog to FK4 catalog on 1962-01-01.
I've changed the former UT1 in that table to:
\item[UT] Earth rotation time. We do not distinguish between UT0, UT1,
and UT2; applications requiring this level of precision need additional
metadata. This should also be used to label GMT times in datasets covering
dates before 1972-01-01.
(volute rev. 5251) and removed the former language on GMT in UTC. Is
that minimally acceptable?
Also, I've put in François' and Mark's proposal of M?JD-origin both
into the text and the draft VOTable schema. Putting it in convinced
me again that it's probably not a good deal in terms of standard
effort vs. possible benefit, but since nobody spoke out against it so
far, it's in now (rev. 5252).
A pre-built draft document is still at
http://docs.g-vo.org/timesys-draft.pdf, the draft schema is in volute
-- unless there's more feedback, this would be what I'd submit as
version 1.1 (except I'll update the frame/refpos enumerations in the
Thanks for the feedback, everyone,
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