Steve Allen wrote on 2004-01-29 00:13 UTC: > While the new paradigm of celestial coordinates is rigorously > defined in terms of mathematics, it is lacking in a common > terminology. [...] > > http://syrte.obspm.fr/iauWGnfa/ > > [...] the fact is that it is > difficult to make sense of the proposals without familiarity > with the past 20 years of literature on coordinate systems.
As a layperson with a good background in mathematics and physics and no fear of dealing with exact definitions relating to multiple frames of reference, I tried a couple of times to understand from available online sources and almanac commentaries the state of the art in astronomic and terrestrial coordinate systems. I failed each time miserably, thanks to the -- in my view -- rather inpenetrable use of obscure terminology and circular definitions. If someone knows of an introductory tutorial that describes the exact definition of modern celestial and terrestrial coordinate systems, without assuming knowledge of any terms other than those of linear algebra and good high-school-level astronomy, I would be most greatful for a pointer. If no such thing exists, then perhaps one of the gurus in the field might be interested in writing such a tutorial for non-astronomers? Something comparable to McCarthy's Astronomical Time in Proc. IEEE 79(7)915-920? Writing such a self-contained tutorial that presents the modern definitions of earth and space coordinate systems independent of the past 20 years of literature might also be a valueable exercise towards coming up with a neat and clean terminology that is free of the accumulated historic ballast that the current terminology in this field seems to suffer from. Perhaps the modern definition of earth and space coordinate systems is now even ripe for being written up as an ISO standard? The editorial guidelines of the International Standards Orgainzation strongly encourage the careful authoring of entirely self-contained specifications that are practically free of undefined or circular terminology. So this might be another very useful exercise towards making this work more accessable and therefore useable by a much larger community. Just a thought ... Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__