is it possible to make an array duplicate along a circal too make a ring or sphere of objects ?
If you add a curve modifier to the sphere and put the array modifier above it in the stack then the instances of the object will be placed along the curve. To make a circle you can just use a bezier circle.
The curve modifier does however deform the mesh, so depending on the scenario, you would use different methods. If you just want a circle of instanced spheres, you can just add a circle mesh, parent a sphere to it and turn dupliverts on.
In the attached .blend file the example on the left uses dupliverts and the one on the right uses curve and array modifiers.
Attachments
Arrays.blend (260 KB)
Make a Sphere. Goto edit mode and go to the top view. Click your left mouse button some where along the Y axis (the direction should be UP if your in the top view) and now you should see a sphere and the little crosshair target away from it. Hit F9 to go to the edit mode then in the Mesh Tools tab under Degr: put 360 and then hit the Spin Dup button.
You might want to adjust it to your liking to get the best fit for you, but when your all done select all the verticies and hit W> remove doubles.
thanks both methods work verry well