\begin{table}%t13
\par
\caption {\label{table:fitnoncanonico}Quadratic analytical relations for the 
  fundamental edges, in the non canonical standard case.}        
%\centering
\par
\begin{tabular}{l l l l}
\hline\hline
 $a$ & $b$ & $c$ & $\sigma$\\
\hline
&Blue edge&&\\
 3.904 $ \pm $  0.046 &--0.034  $ \pm $ 0.027  & --0.0001 $ \pm $ 0.0038 & 0.002 \\
&Red edge&&\\
3.816 $ \pm $  0.078  & 0.008 $ \pm $ 0.046  & --0.0124 $ \pm $ 0.0065  & 0.004 \\
\hline   
\end{tabular}
\end{table}