Showing results for 
Search instead for 
Did you mean: 

Planet Orbits

@DFGray wrote:

I programmed this exact problem (in 2D) using FORTRAN IV on a DECSystem 20 mainframe many years ago.  I still have the printout and a couple of traces from a TEK4014 graphics terminal in my shelves.  I think I even still have the handwritten equations of motion out to about fifth order.  A couple of things you may want to do:


  1. Dynamically vary your dt bases on error estimates.  You can estimate your error if you expand the simple first order approximation (a1 + a2t) into higher orders.  You can use the value of the last term in your expansion as an error approximation, then set your step size to achieve the error you want to see.  Your code with approximately double for each order you add, but your step size will go up by about an order of magnitude at the same time.
  2. LabVIEW has 3D controls, so you can calculate and plot your results in three dimensions.
  3. If you are in to pain, you can use the same equations to calculate the trajectories of charged particles - but you will need to add the effects of the moving electric fields...

Aaah ok, I think I understand, if you have a copy of the equations of motion, I would love to have a  look since I am a little lost. If not then no worries, I will try a few other things:)

0 Kudos
Message 11 of 13

Here you go.  I included the relevant parts of the paper.  It was dated 1981.

This account is no longer active. Contact ShadesOfGray for current posts and information.
0 Kudos
Message 12 of 13

@DFGray wrote:

Here you go.  I included the relevant parts of the paper.  It was dated 1981.

Wow, thanks a lot!:D

0 Kudos
Message 13 of 13