NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: half-hour time zones
From: Brian Whatcott
Date: 2001 Nov 03, 4:34 AM
From: Brian Whatcott
Date: 2001 Nov 03, 4:34 AM
At 06:44 PM 11/2/01 -0800, you wrote: >Anyone know why some places have time offsets not an integral number >of hours from Greenwich? Like Newfoundland. /// >paulhirose@earthlink.net (Paul Hirose) Once upon a time, people used a natural means of setting a time reference, by inspection of the Sun's meridian crossing (though they might prefer to postpone their lunch break to a few hours later, at the hottest time of day, once called 'noon'). Then the railroad engine was developed in a compact country where holding a common time standard was no inconvenience. It soon spread to Russia and USA where the Sun takes several hours to transit. For railroad schedulers, this was a nightmare - and wasn't much fun for continental travellers. Greenwich competed successfully with Paris Mean Time as a time standard for marine navigators, and so some means of indexing time zones from Greenwich was hit on as a means of bringing order to the railroad schedule. The trick was to draw lines on the map which avoided large conurbations, as far as possible. Having neighbors in a town operating at one hour offsets would not be a pleasant sight. And so an Eastern, Central, Mountain, and Pacific time zone was decided, which worked well in general - though in particular, there were difficulties. To mention just two: near Chicago, where there were several towns near a boundary, another east of Eastern time zone where there was not enough territory for the 'center of gravity' for the territory to be one hour earlier. They chose a half hour decrement to keep the local noon (modern sense) near the clock noon. [I have slightly dramatized this story, hopefully without blurring the messy truth excessively] Brian W