On Mar 18, 2010, at 12:47 PM, Patrik Fältström wrote:
On 18 mar 2010, at 17.38, Marshall Eubanks wrote:
This is backwards. Most astronomers I know regard UTC as a
nuisance. In their calculations, astronomers use TAI (or, if they
need to know the rotation of the Earth, UT1). Solar system
ephemeris work uses ephemeris time, for historical reasons (ET −
TAI = 32.184 seconds). GPS internally uses GPS time, which has the
leap second adjustment appropriate for the start of the series in
1980, supposedly because the GPS program office didn't understand
leap seconds (TAI - GPS = 19 seconds).
Hmm...the signal for the GPS include the difference nowadays, right?
This is the internal time standard. GPS receivers report UTC.
Marshall
But, the largest problem I think are daylight savings, and the fact
the daylight savings rules change.
We should from IETF point of view review the ical spec, and try to
push timezone information away from the objects, and to a central
repository. The timezone offset should be calculated based on the
geographical location of the event.
I.e. if I (or my application) know something happened at 13:32 on
2010-01-02 in Stockholm, that is I claim the best way of stating
when something happened. Even better example is 13:32 at 2123-01-02
in Stockholm, as the chance Stockholm still exists in 2123 is higher
than Stockholm use the same daylight savings rule then compared with
today.
Of course one should be able to say explicit time related to UTC (or
TAI ;-) ) as well, but...I am tired of all applications that do the
wrong thing. Specifically in user interfaces.
Patrik
_______________________________________________
Ietf mailing list
Ietf(_at_)ietf(_dot_)org
https://www.ietf.org/mailman/listinfo/ietf