TIMESYS Note 1.1

[Markus Demleitner]

Dear Apps WG, dear Time Domain WG,

Version 1.1 of the Note proposing TIMESYS has hit the document
repository, http://ivoa.net/documents/Notes/TimeSys/20181212/

I hope I have incorporated the results of the discussions in the past
seven weeks (thanks again to all who contributed!)

The main changes are:

* Now allowing magic strings MJD-origin and JD-origin in the
  timeorigin attribute.
* Fixed _MJD example (which was plain broken in 1.0).
* Replacing UT1 timescale with UT (reviewers remarked that actual UT1
  should be extremely rare in practice).
* Improved descriptions of a few time scales based on reviewer feedback.

If you've wanted to have a look at that thing before but then waited
because you wanted to see where it goes -- this would be the perfect
moment to read it.  Early in January I'd essentially implant a redux
of this (i.e., about the opening paragraphs of this) into the VOTable
specification and produce WD-VOTable-1.4 -- the more contentious
points we've covered before that the faster that should work out.  

As
envisioned, the refpositions and timescales will go into
vocabularies.  There are already drafts of these:
http://docs.g-vo.org/rdf/refposition and
http://docs.g-vo.org/rdf/timescale (with release dates that I'd
consider ambitious but might just work for a PR).  They just reflect
the tables in the note at this point.

Thanks,

        Markus