[time-nuts] GMT vs. UTC

Magnus Danielson cfmd at bredband.net
Mon Nov 20 17:32:06 EST 2006


From: Magne Mæhre <magne at samfundet.no>
Subject: Re: [time-nuts] GMT vs. UTC
Date: Mon, 20 Nov 2006 21:36:31 +0100
Message-ID: <456211CF.7010006 at samfundet.no>

Magne,

> Magnus Danielson wrote:
> > The question relates to weither GMT and UTC is the same time-scale or not.
> > If they are not, what is the difference? Where would I find any authority
> > information showing that they are the same or are not the same.
> > 
> > Now, if you would write law, which one would you use, GMT or UTC?
> > Personally, I would go for UTC (since I understand its connection to TAI).
> > GMT? I am not sure.
> 
> Hi Magnus.
> Since you're probably in Sweden, it may be relevant to look at SFS
> 1979:988, which defines Swedish Standard Time (in short, it is defined
> to be UTC + 1 hour)

SFS 1979:988 is short and clear.
SFS 2001:127 is short and not so very clear, and does not match the English or
Swedish translations of the European Directive on summertime on the particular
aspect of GMT or UTC. It only works relative SFS 1979:988 which is UTC where as
the Directive says GMT. If they is not they same, then theres an interesting
problem. The irony in it all is that it was the swedish govrement that brought
the directive into play and at the same time wrote the law. Ah well, laws are
way to important to leave to laweyrs!!! :P

> The swedish national time scale (UTC(SP)) is maintained by Sveriges
> Provnings- och Forskningsinstitut (SP).  See link below.

Been there, have nice photos and padded UTC(SP). Have good relations with them.

> For a introduction to the difference between UTC, GMT, UT0, UT1 etc. , I
> suggest the wikipedia article on UTC. Link below.

I did look there, and it doesn't gave a clear enought answer, however, this is
clearer:
http://en.wikipedia.org/wiki/Greenwich_Mean_Time#Time_zone

GMT is a UTC derivate these days. At least for 10 of the identified 11
translations for summer time shall use UTC rather that GMT. Actually, I think
all 11 should use UTC.

Cheers,
Magnus



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