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Perihelion Pass Dates?

  1. Jun 30, 2008 #1

    I am writing a basic javascript orrery which will display the position of the planets orbiting the sun. Using keplers equation I am going to find the true anomaly and the radius at the current time and then plot the points to a 2d grid.

    The problem is I need to know the time that has elapsed since perihelion so I can calculate the Mean anomaly. I plan to use the iterative Newton method to get the Eccentric Anaomaly and from that work out the true anomaly.

    Do you guys know where I can find a list of previous perihelion dates where the planets were at their closest approach?

  2. jcsd
  3. Jun 30, 2008 #2


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    Staff: Mentor

  4. Jun 30, 2008 #3

    D H

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    The definitive source of ephemeris data is the HORIZONS system at JPL. Website: http://ssd.jpl.nasa.gov/?horizons.
  5. Jun 30, 2008 #4
    It's nice that that site still lists that we have '9 planets'.
  6. Jun 30, 2008 #5
    BAH! Semantics !:rolleyes:
  7. Jun 30, 2008 #6
    Thanks guys

    Ill check out the site tommorow looks like ill have to do a bit more in depth reading onto all the different parrameters ive not really covered this stuff in my course yet but so far I see its just basic trig geometry.


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