[time-nuts] French Time offset

Magnus Danielson magnus at rubidium.dyndns.org
Wed Mar 18 23:11:22 UTC 2009


Lux, James P skrev:
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com 
>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Jean-Louis Oneto
>> Sent: Wednesday, March 18, 2009 10:14 AM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] French Time offset
>>
>> BIPM is an _international_ organisation, and apart to be in 
>> France, has nothing to do (and never had as far as I know) 
>> with the definition of French legal time. At least no more 
>> than for any other country UTC (or TAI) based.
>> Jean-Louis
>>> Paris is at 2degrees 20 min longitude, which isn't enough 
>> to account 
>>> for
>>> 12.5 minutes.  Sevres (where BIPM is) is actually a bit to 
>> the west, 
>>> so even less solar time difference.
> 
> 
> Just casting about for potential meridian locations that might explain the 12.5 minute difference. Maybe the central longitude of France is 12.5 minutes(of time, 3 1/8th degrees of longitude) from Greenwich? (like India's time zone being on the half hour). Things get done for funny reasons: After all, the physical size of France is why ATM "cells" (packets) are 53 bytes (48 byte payload) instead of either 32 byte or 64 byte payloads.

If you look at the map Arnold linked to, you will see that France sits 
very neatly into the Zulu-timezone. Infact, France is better served by 
it then GB. I have enjoyed the incorrectness of France time-zone-wise on 
my many travels to France, so I am not complaining from a practical 
point of view, but it would not be my first choice if I would choose 
something for France.

Map:
http://media4.obspm.fr/public/amc/images/mesure-temps/images/849.gif

Cheers,
Magnus




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