Re: Applications of earth-orientation information

From: Markus Kuhn <>
Date: Thu, 24 Jul 2003 15:15:35 +0100

Ed Davies wrote on 2003-07-24 11:12 UTC:
> Perhaps a way of moving the discussion on would be to make a
> list of applications requiring accurate Earth orientation
> information:
> 1. Pointing telescopes.
> 2. Pointing satellite dishes.
> 3. Celestial navigation.
> 4. Calculating the civil times of sunrise and sunset, lighting
> up times, etc.
> Others?

Not many more, I guess. Perhaps:

 - Sundail designers and owners (will have to add an additional
   term to the equation of time)

 - Computer-aided design software used by architects for predicting shadows,
   illumination and thermal load. But I doubt they need (or use currently)
   the local solar time to within better than 30 minutes, and they are more
   interested for how many minutes a day the sun shines through a window,
   and less, at what exact (meaning < 30 min tolerance) civilian time
   this starts and ends.

Don't forget in this discussion that abandoning leap seconds will only
increase the maximum difference between local civilian time and local
solar time from currently 30 minutes (at places such as China and
Western Europe much worse) to 60 minutes, because as long as DST is in
use, local civilian times will have very little problems following local
solar time with leap hours.


Markus Kuhn, Computer Lab, Univ of Cambridge, GB | __oo_O..O_oo__
Received on Thu Jul 24 2003 - 07:15:53 PDT

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