On Sep 1, 2005, at 7:46 AM, John.Cowan wrote:
The table can be downloaded from http://www.ccil.org/~cowan/zone- changes.txt .
Data - cool! Thanks.
The first column is the zone name in the form "continent/ city" (city names are more stable than country or state/province names).
Yeah, that's what Apple does, for instance, in their timezone preferences. Note that this really wants to be a list of political/ geographic entities with the authority to make their own choices, not simply a list of ones who have done so in the past. That the Hopi Nation is in the same timezone as Arizona may or may not be up to them. Whether they observe DST and with what rules is a matter of their sovereignty.
Just as a matter of interest, I also discovered that as of right now there are 37 different time offsets in use: the integral hour offsets from -11h to +14h, plus the following: -9h30m (Pacific/Marquesas), -3h30m (America/St_Johns), +3h30m (Asia/Tehran), +4h30m (Asia/Kabul), +5h30m (Asia/Calcutta), +5h45m (Asia/Katmandu), +6h30m (Asia/Rangoon), +9h30m (the Yellow-Dog Dingo zones), +10h30m (Australia/Lord_Howe), +11h30m (Pacific/Norfolk), and +12h45m (Pacific/Chatham).
Isn't this clear evidence that societies worldwide recognize the primacy of solar time? What possible explanation other than synchronization with the sun (or stars) could be offered for a quarter or half hour offset? Clearly these localities would regard noon=light and midnight=dark as too course a constraint. Whatever solutions are entertained to the challenge of civil time, an appropriate recognition of solar time should be included in the requirements.
Of course there are means of coordinating them. The EU is one such means, and the federal U.S. and Australian governments are another. But in the end LCT is an attribute of sovereignty, and individual governments will give up just as much control as suits them.
Indeed, but one might expect that these governments would prefer to be given some hints from the experts as to appropriate policies. The notion of a leap hour may or may not correspond to appropriate policy. Wouldn't it be easier to make the case in support of this policy change if there were some detailed plan developed for what effect leap hours and large values of DUT1 might have in the future? Might not officials from the Marquesas through Chatham, let alone Tehran and Calcutta, wish to be consulted and advised? Rob Seaman National Optical Astronomy Observatory
