> **Possible Duplicate:**  
> [Difference in Plot when using Evaluate vs when not using Evaluate](https://mathematica.stackexchange.com/questions/1731/difference-in-plot-when-using-evaluate-vs-when-not-using-evaluate)  

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I am plotting galaxies and I would like to color them according to their redshift values using a temperature map as a metaphor for shifted wavelengths. Here, I will assume that a circle has a redshift value corresponding to its radius. How would one assign a different color to each circle using a temperature map with hue from blue to red corresponding to increasing size?

    circle[Theta_, r_] := {r*Cos[Theta], r*Sin[Theta]};
    ParametricPlot[Table[circle[Theta, r], {r, 1, 5}], {Theta, 0, 2 Pi}]