\begin{table}%t2 \caption{\label{annual_results}Results of power-law fits to the VHE spectra of H~2356--309.} %\centering \par \begin{tabular}{c c c c c c c c} \hline\hline \noalign{\smallskip} Epoch & $E_{\rm min}$ & $E_{\max}$ & $\Gamma$ & $I_{\circ}$\tablefootmark{a} & $\chi^2$ & NDF & $P(\chi^2)$\\ & [TeV] & [TeV] & & [$10^{-13}$ cm$^{-2}$ s$^{-1}$ TeV$^{-1}$] & & & \\ \noalign{\smallskip} \hline \noalign{\smallskip} 2004 (AH06)\tablefootmark{b} & 0.165 & 1.041 & $3.06 \pm 0.21_{\rm stat} \pm 0.10_{\rm syst}$ & $3.08 \pm 0.75_{\rm stat} \pm 0.62_{\rm syst}$ & 3.9 & 6 & 0.69 \\ \noalign{\smallskip} \hline \noalign{\smallskip} 2004\tablefootmark{c} & 0.200 & 1.500 & $2.97 \pm 0.19_{\rm stat} \pm 0.10_{\rm syst}$ & $4.69 \pm 0.86_{\rm stat} \pm 0.94_{\rm syst}$ & 7.8 & 5 & 0.17\\ 2005$^{\hspace{0.1cm}}$ & 0.200 & 2.000 & $2.99 \pm 0.39_{\rm stat} \pm 0.10_{\rm syst}$ & $2.92 \pm 0.89_{\rm stat} \pm 0.58_{\rm syst}$ & 5.0 & 6 & 0.55\\ 2006\tablefootmark{d} & 0.200 & 2.000 & $3.43 \pm 0.41_{\rm stat} \pm 0.10_{\rm syst}$ & $2.13 \pm 0.79_{\rm stat} \pm 0.43_{\rm syst}$ & 0.7 & 2 & 0.70\\ \noalign{\smallskip} \hline \noalign{\smallskip} Total & 0.200 & 2.000 & $3.06 \pm 0.15_{\rm stat} \pm 0.10_{\rm syst}$ & $3.29 \pm 0.45_{\rm stat} \pm 0.66_{\rm syst}$ & 5.7 & 6 & 0.47\\ \noalign{\smallskip} \hline \end{tabular} \tablefoot{\tablefoottext{a}{The differential flux normalization is calculated at 1~TeV.} \tablefoottext{b}{The AH06 entry is the previously published HESS result (\cite{HESS_discovery}) for the 2004 data and is not corrected for long-term changes in the optical efficiency of the system.} \tablefoottext{c}{This 2004 entry is derived from the exact same data as presented in AH06, but with a correction (see text) applied to account for the optical efficiency changes within the data. The 2005, 2006 and total entries also have this correction applied.} \tablefoottext{d}{Due to low statistics, the 2006 spectrum is determined using 4~bins/decade in energy instead of the 8~bins/decade used for the other photon spectra.}} \end{table}