1 Reply Latest reply on Nov 11, 2014 2:10 PM by Matperry-Oracle

    Fundamental spatial coordinate systems. WGS84 vs RA/DEC

    joguerra

      Hi,

      I have some sort of fundamental question about the Oracle Spatial feature and its coordinate model. As far as I am aware of, Oracle use WGS84 coordinate reference but I am pretty much interested on RA/DEC. RA/DEC are used for astronomy as a reference system and my question is whether anybody knows how to map RA/DEC into WGS84 and in the other way around. I know that LATITUDE=DEC but LONGITUDE !=RA.

       

      I know that we can assume that a negative longitude in WGS84 is west of Greenwich than we'd get LONGITUDE = RA*15 and LATITUDE = DEC. The celestial longitude RA=0 through the vernal equinox would then be projected on the meridian of Greenwich. The problem is that I don't know about the accuracy of this assumptions.

       

      I post this query here because I am using GeoSPARQL and Oracle semantic database to try to model part of the Sky. Maybe I should post the query on the Spatial forum, but please let me know!

      Cheers