[tz] Official time zone rule sources

Glenn Eychaner geychaner at mac.com
Fri Oct 21 13:05:20 UTC 2011

	As someone who has been following this list for a few years, and even made a couple of contributions to the data, I think the current mechanism is just fine. It's not as though people are simply pulling changes out of a hat.  People with a genuine, vested interest in accurate time information (like the Las Campanas Observatory in Chile in my case) are assisting in the timely and accurate compilation of that information.
	At least some cases, the "informal" process depends on pre-existing formal mechanisms.  For example, U.S. time information (DST rules, official time, etc.), can be found at NIST Time and Frequency Division and the USNO Time Service Department:
while for Chile, the same information can be found at the Servicio Hidrográfico y Oceanográfico (SHOA):
and the raw text database generally contains references to these formal web sites in the commentary, as well as to newspaper articles or other external sources, whenever a change is made.  (In fact, there is an astounding amount of commentary in the raw text database, some of which I have contributed for Chile.)  Perhaps the textual databases should contain a list of these official time sources for each country?  Maybe the official URLs (when available) could even be made accessible through the API in some way, rather than just in the text commentary (or maybe not; I'm not sure whether this is a good idea or not; I'm just opening it for discussion)?
	In some cases, as has been pointed out, the "formal" mechanisms are insufficient; the database is intended to represent how people actually set their clocks, rather than how governments say people should set their clocks.  The database also contains considerable historical information, which the offical sources don't always make available (though the SHOA has a very nice summary at
which sometime I should compare with the database to see if it's accurate.)

"Oh, ho ho! You sly dog! You got me monologuing! I can't believe it... "

Glenn Eychaner (geychaner at lco.cl)
Telescope Systems Programmer, Las Campanas Observatory

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