Create an animation of planet in an elliptical orbit?

Questions
, ,
1

I use Mathematica 7
I am trying to animate a planet (Disk in Mathematica) on an elliptical orbit whose ContourPlot is found from:

plot1=ContourPlot[x^2 + 2 y^2 == 3, {x, -1.75, 1.75}, {y, -1.75, 1.75}, 
 ContourStyle -> {Red, Thickness[0.0025]}, Frame -> False, 
Axes -> True ]

using an input from an earlier version of Mathematica, which is:

plot2=Animate[{plot1,
Graphics[{RGBColor[0, 0, 1], 
    Disk[{Sqrt[3] Sin[x], Sqrt[3/2] Cos[x]}, 0.1]}]}, {x, 0, 2 \[Pi], 
  0.3}, PlotRange -> {{-1.9, 1.9}, {-1.5, 1.5}}]

This does not work.
I shall be grateful if someone could help me to find the correct code for animation for Mathematica 7

2

This code works for me. Btw these days i am reading tutorial/IntroductionToControlObjects

Animate[
 Show[
  {plot1
   , Graphics[{
     RGBColor[0, 0, 1]
     , Disk[{Sqrt[3] Sin[x], Sqrt[3/2] Cos[x]}, 0.1]
     }]
   }, PlotRange -> {{-1.9, 1.9}, {-1.5, 1.5}}
  ], {x, 0, 2 Pi, 0.3}
 ]
3

I think the trick is that you should use Show to combine the different graphics. See attached . nb

WCom.nb (91.1 KB)

4

Thank you so much Raspi. This has been a great help. Regards. Mohammad

5

Thank you very much Hans. This has been extremely helpful. I should have thought about he Show command. Regards. Mohammad