[Numpy-discussion] RFC: A proposal for implementing some date/time types in NumPy

Anne Archibald peridot.faceted@gmail....
Fri Jul 11 19:17:23 CDT 2008


2008/7/11 Jon Wright <wright@esrf.fr>:

> Timezones are a heck of a problem if you want to be accurate. You are
> talking about nanosecond resolutions, however, atomic clocks in orbit
> apparently suffer from relativistic corrections of the order 38000
> nanoseconds per day [1]. What will you do about data recorded on the
> international space station? Getting into time formats at this level
> seems to be rather complicated - there is no absolute time you can
> reference to - it is all relative :-)

This particular issue turns up in pulsar timing; if you use X-ray
observations, the satellite's orbit introduces all kinds of time
variations. If you care about this you need to think about using (say)
TAI, referenced to (say) the solar system barycenter (if there were no
mass there). You can do all this, but I think it's out of scope for an
ordinary date/time class.

Anne


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