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Need help finding exact time of planet aspects with Jean Meeus library

  1. Jul 11, 2014 #1
    I am using the C library that comes with the book Astronomical Algorithms by Jean Meeus http://www.willbell.com/math/mc1.htm

    This book and C library has a calculation for two planets Conjunction and Opposition but no other planet aspects. Does anyone know a method to find when two planets are a fixed degree apart such as 90 degrees, 120 degrees or any other degree?

    The problem I have run into is that geocentric planets move through a retrograde and direct cycle. As an outer planet approaches the transition from retrograde to direct it is almost stationary at which time I can not calculate any accurate degree of separation. So I need a proven method to calculate the date-time of exact angular separate even when two planets are almost stationary.

    Any advice would be appreciated.

  2. jcsd
  3. Jul 14, 2014 #2
    I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?
  4. Jul 15, 2014 #3
    I think you're looking for a "Fundamental Solar System ephemeris".
    I have never used such a thing, but there seems to be something useful at this site: http://ssd.jpl.nasa.gov/
  5. Aug 5, 2014 #4
    The only way to do this exactly is to run a full-blown ephemeris of the Solar System and interpolate. Meeus gives you some handy formulae to approximate a number of interesting configurations, but these are indeed approximations boiled down from the full ephemera.
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