[ntp:questions] Re: GMT: UT1 vs UTC

David L. Mills mills at udel.edu
Fri Oct 31 19:14:13 UTC 2003


Terje,

We can do this. Provisions are in the nanotime kernel interface to
return the TAI seconds offset in the ntp_gettime() routine. We could
format that offset in deciseconds instead. It would not be hard to
modify the clock drivers to include the DUT1 value and add this to the
offset from the leapseconds file. Is this worth doing?

Geeze, I suppose we could determine the TDB correction from the
geographic position (with a little help from an almanac) and return that
as well. Somebody should volunteer a driver for the stepper motors that
drive you telescope, which would then become completely automatic. This
would be an interesting class project.

Dave

Terje Mathisen wrote:
... 
> Afaik, not being an astronomer like you, the standard procedure is to
> use the current UTC, or if known, UT1 approximation, to point the
> telescopes in approximately the correct direction, then do any remaining
> fine-tuning by selection of one or more calibration stars.
> 
> I.e. effectively generating the local UT time scale, corrected also for
> stuff like temperature or Earthquake-caused twisting of the base of the
> observatory, right?
...



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