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    Re: Prime Meridian
    From: Paul Hirose
    Date: 2014 Mar 18, 16:45 -0700

    Jackson McDonald wrote:
    > Next there were tedious, scientific (and not-so-scientific) deliberations 
    about whether meridians of longitude should be measured 360 degrees from west 
    to east, 360 degrees from east to west, or 180 degrees both east and west of 
    the Prime Meridian.
    
    There's still no universal convention. Astronomy sometimes measures
    terrestrial longitude east to 360. For example, the JPL HORIZONS system
    will accept longitude -150 (= 150 west) or the equivalent +210 for the
    observing site, but in either case its output says +210.
    
    I have had to adjust longitudes with a calculator because they were
    "illegal" according to the program I was trying to use. Writers of
    astronomical software, don't get too zealous with your error checking.
    
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