[tz] Reason for removal of several TZ

Steve Allen sla at ucolick.org
Mon Dec 4 19:16:42 UTC 2017

On Mon 2017-12-04T10:37:35-0800 Paul Eggert hath writ:
> Come to think of it, it's worth documenting the Dublin/Dunsink issue a bit
> more, including the question whether DMT was -00:25:21.1 or -00:25:22. It's
> possible that we're missing an 0.9-second transition for Dublin/Dunsink
> circa 1896, which presumably we'd model as a 1-second-transition! I'll leave
> that just as a comment for now. I installed the second attached patch, plus
> the third to fix a typo.

Thumbing through early issues of Bulletin Horaire, the journal of the
International Time Bureau (BIH), quickly shows that actual times
provided by observatories as the legal times for various jurisdictions
commonly had varying offsets of many tenths of seconds from the
intended times indicated by official documents.

There are not many contenders for a more boring publication than the
nearly 100 years of tabulations of how wrong various official clocks
have been, but nestled in the introductions to each issue there are
other passing references about when various observatories changed
their rules, algorithms, and/or conventional longitudes and thus had a
leap in the time they provided to their region.

Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat  +36.99855
1156 High Street               Voice: +1 831 459 3046         Lng -122.06015
Santa Cruz, CA 95064           http://www.ucolick.org/~sla/   Hgt +250 m

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