transform with rotate and translate

You rotate and transform the new (translated and rotated) copy of the original object. Since the x translation is the same, your objects appear spaced out at 47 pt horizontally; the y translation stays the same, so the object does not move vertically.

The rotation, on the other hand, gets applied incrementally -- the first copy is rotated by 20°, the second by 40°.

The Transform Filter also rotates both the x and y translations by the same angle, so the original object moves 'up, up and away'.

I ran into some problems trying the same with each next duplicate, so instead I do each translation-and-rotation on the original object (I'm sure it's just a question of maths to get that right, but in this case it's virtually of no importance since the end result is the same). I increase the angle of rotation and concatenate the Verschiebung with its previous value. Voila: the same result.

(A difference is that I tested with CS4, and in that the Transform effect dialog still has the nine-point rotation origin proxy. In your version -- CS6 -- it's strangely missing.)

dupItems = 3;
selectedObject = app.selection[0];
displacement_x = 47;
displacement_y = 0;
myRotation = 20;
for (i = 0; i < dupItems; i++)
{
dupObj = selectedObject.duplicate();
dupObj.translate(displacement_x, displacement_y);
dupObj.rotate(myRotation
  ,true
  ,false
  ,false
  ,false
  ,Transformation.CENTER);
// selectedObject = dupObj;
displacement_x += 47*Math.cos(myRotation*Math.PI/180);
displacement_y += 47*Math.sin(myRotation*Math.PI/180);
myRotation += 20;
}