STC ObservationLocation

[Arnold Rots]

Yes, and if you happened to be using an HP-35 your ln(2) value might
be off...
I wasn't suggesting that mistakes were made - the reasons might be the
availability of a better position, or a comparison with data based on
a different solar system ephemeris (say, DE200 instead of DE405).
Of course there are cases where it does not matter.  In many cases I
don't care what time zone email messages addressed to me came from;
but nobody objects to that information being in the header.
Can we close this discussion?

  - Arnold

Roy Williams wrote:
> 
> > If you say BARY, it means you have applied a transformation.  And that
> > transformation is based on model assumptions.
> > There are a number of applications where it is crucial that users can
> > undo that transformation (the obvious one being pulsar timing).
> 
> So the obseratory location plays two semantic roles: one for TOPO  
> (where it is strictly necessary) and one for GEO, where it is  
> necessary to provide computational provenance in case of mistakes.
> 
> In that case, I suggest that other elements be mandatory. Perhaps the  
> time-zone where the time measurement was made? It is possible that  
> the time-zone conversion was not done properly -- in which case it is  
> equally crucial that users can undo that transformation. I for one  
> never know whether we are on summer time or not.
> 
> I suggest to you that in some cases the transformation from TOPO to  
> GEO is very simple, and in these cases it is not necessary to pass  
> the time-zone or the observatory location. Specifically, if the  
> object is distant and the error in timing of the event is much larger  
> than light-time across the Earth.
> 
> Roy
> 
> 
> 
> California Institute of Technology
> 626 395 3670
> 
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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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