title: Transformation of logarithmic function & scaling
body: <p>So I need to do this:</p>
  
  <p>Define a suitable fitting function, "Planck(l, *p)" to the experimental data of the Planck function. This function is to be based on the Planck formula:</p>
  
  <pre><code>Bλ(T) = (2hc^2/l^5) / (exp(hc/klt) -1)  
  </code></pre>
  
  <p>, where <strong>l</strong> is the set of wavelengths, <strong>k</strong> is Boltzmann’s constant, <strong>h</strong> is Planck’s constant and <strong>c</strong> is the speed of light.<br/>
  I need to have 2 fitting parameters in <strong>p</strong>, one will be <strong>T</strong> (temperature) and the other is going to be a scaling factor.</p>
  
  <p>I plotted out the experimental data and the fitting function for a <strong>T</strong> which I found through trial-and-error so that its peak is equal to the data's peak and this is my result:
  <a href="https://i.stack.imgur.com/tL1TH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tL1TH.png" alt="plot"></a>
  So apparently, I somehow need to transform the blue function in order for it to fall onto the experimental data, supposedly via the scale factor. What is a scale factor and how can I use it to move the whole graph 5 units to the right?
  This is a logarithmic plot so things like <code>y=x^2 ==&gt; y=(x-5)^2</code> <strong>won't work</strong>.
  Any ideas please?</p>
  
  <p>I am using <code>curve_fit</code> to fit the data.</p>