Thanks for the file, and thanks for using DropBox.
In your file, the rendering was set to Anti Alias> Geometry. This will not give the best idea of texture. I have set it to Sinc, which is a little bit harsh for a typical scene (i.e., I don’t use it), but here it makes sense. AA> MIP50%
Here is your file back, with a little addition, as well as an alternative.
You might wonder why I use the deformer twice. I got better results working in steps and more refined control with the Falloff.
The Time Effector in your scene is set to Deform> Object. Which allows for a constant rotation without having to deal with keyframes.
I checked to use a cone instead, also here, I set the AA to Sinc, and again, the AA> MIP value to 0%. Render in the Picture Viewer! This will give you a Siemens-Star as much as the pixels of your screen allow for.
Let me know if you need anything else; I’m happy to look into it.
Click thumbnail to see full-size image