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<div class="">On 2016-05 -10, at 21:10, Arnold Rots <<a href="mailto:arots@cfa.harvard.edu" class="">arots@cfa.harvard.edu</a>> wrote:</div>
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<div class="">I don't have the text of ISO-8601 handy here, but my recollection<br class="">
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was that it is silent on what a time stamp without explicit time zone<br class="">
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I do not have a copy of the text of ISO-8601 either, but many authoritative sources make this interpretation clear e.g. <a href="https://www.cl.cam.ac.uk/~mgk25/iso-time.html#zone" class="">https://www.cl.cam.ac.uk/~mgk25/iso-time.html#zone</a> , <a href="https://en.wikipedia.org/wiki/ISO_8601#Times" class="">https://en.wikipedia.org/wiki/ISO_8601#Times</a> and
that is how java <a href="https://docs.oracle.com/javase/8/docs/api/java/time/package-summary.html" class="">https://docs.oracle.com/javase/8/docs/api/java/time/package-summary.html</a> interprets strings for instance and <a href="http://tools.ietf.org/html/rfc3339" class="">http://tools.ietf.org/html/rfc3339</a> recommends
UTC but adds the Z to be explicit.</div>
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<div>There are a wide range of existing software systems (e.g. language libraries, databases) that use the strict interpretation of ISO-8601 which mean that the timestamp without will be interpreted incorrectly unless the system timezone is set to UTC, and
while I can imagine that many astronomical servers around the world do have their timezones set to UTC, I doubt that all astronomers laptops are similarly set with their timezone to UTC.</div>
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<div class="">Be that as it may, it does not explicitly allow for attaching time scale<br class="">
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labels to the date-time strings and hence pairing a bare string with<br class="">
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<div class="">a time scale is a reasonable thing to do.<br class="">
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<div class="">Pure use of JD or MJD is problematic if UTC is an allowed time<br class="">
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<div class="">scale, since their values are ill-defined during days with leap seconds.<br class="">
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<div class="">Besides, the date-time strings are nicely human readable.<br class="">
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This issue is why I made the suggestion earlier in this thread that only ISO 8601 be used only for the case of UTC timescale and be forbidden for other timescales - then the Z serves the double purpose of being a designator of UTC timezone and time scale whilst
keeping compatibility with non-astronomical ISO 8601 usage.</div>
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<div>Cheers,</div>
<div><span class="Apple-tab-span" style="white-space:pre"></span>Paul.</div>
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