[PW] Historical time zones in the US

Anton Sherwood bronto at pobox.com
Mon Aug 22 14:34:46 PDT 2016


On 2016-8-21 15:31, Gary Lee Phillips reported that the two cities of 
Bristol
> Have both followed the same time zone changes since November 18, 1883
> when standard time was first instituted in the US. Prior to that, both
> towns used local mean time determined by setting noon to match the time
> when the sun crosses due south.

If it was set by the sun each day, that's not mean time.  The difference 
between mean time and sundial time varies by half an hour over the year. 
  https://en.wikipedia.org/wiki/Equation_of_time

The definition of mean time is rather interesting; see 
https://en.wikipedia.org/wiki/Solar_time#Mean_solar_time

-- 
*\\*  Anton Sherwood  *\\*  www.bendwavy.org


More information about the Project-wombat mailing list