\begin{table}%t6
\caption{Structural parameters measured in the RDPs built with colour--magnitude filtered photometry.}\label{tab6}
%\renewcommand{\tabcolsep}{2.95mm} 
\small %\centerline
 {\begin{tabular}{lccccccccc}
\hline\hline
&&&\multicolumn{7}{c}{RDP}\\
\cline{4-10}
Cluster&$1\arcmin$&&$\sigma_{bg}$&$\sigma_0$&$\delta_c$&\rc&\rl&\rc&\rl \\
       &(pc)&&$\rm(stars~pc^{-2})$&$\rm(stars~pc^{-2})$&&(pc)&(pc)&(\arcmin)&(\arcmin)\\
(1)&(2)&&(3)&(4)&(5)&(6)&(7)&(8)&(9)\\
\hline
Be~23   &1.931&&$0.6\pm0.1$&$4.1\pm1.2$&$8.3\pm2.2$&$1.1\pm0.3$ &$10.0\pm2.0$ &$0.55\pm0.15$&$5.2\pm1.0$\\
Be~69   &1.000&&$1.9\pm0.1$&$14.0\pm3.9$&$8.5\pm2.1$&$0.8\pm0.2$&$5.1\pm0.2$ &$0.80\pm0.16$&$5.1\pm0.2$\\
Be~71   &0.862&&$5.5\pm0.1$&$15.5\pm4.7$&$3.8\pm0.8$&$0.8\pm0.2$&$4.9\pm0.2$ &$0.92\pm0.21$&$5.7\pm0.2$\\
Cz~23   &0.728&&$5.2\pm0.1$&$31.1\pm9.0$&$7.0\pm1.7$&$0.4\pm0.1$&$3.6\pm0.1$ &$0.49\pm0.04$&$4.9\pm0.7$\\
NGC~1798&1.731&&$1.2\pm0.1$&$5.6\pm1.9$&$5.5\pm1.5$&$1.4\pm0.4$ &$13.0\pm2.0$ &$0.82\pm0.21$&$7.5\pm1.1$\\
NGC~1883&1.083&&$1.8\pm0.1$&$13.6\pm3.1$&$8.5\pm1.7$&$0.9\pm0.1$ &$10.0\pm1.0$ &$0.82\pm0.13$&$9.2\pm1.1$\\
NGC~2126&0.298&&$11.8\pm0.2$&$49.6\pm17.0$&$5.2\pm1.4$&$0.4\pm0.1$ &$3.5\pm0.5$ &$1.34\pm0.33$&$11.7\pm1.7$\\
FSR~756&0.521&&$2.9\pm0.1$&$36.0\pm17.0$&$13.5\pm5.9$&$0.2\pm0.1$ &$2.2\pm0.3$ &$0.31\pm0.19$&$4.2\pm0.6$\\
FSR~814 &0.475&&$16.5\pm0.2$&$22.6\pm10.2$&$2.4\pm0.6$&$0.6\pm0.2$ &$2.5\pm0.2$ &$1.24\pm0.44$&$5.3\pm0.4$\\
FSR~869 &1.232&&$2.3\pm0.1$&$5.6\pm2.9$&$3.5\pm1.3$&$0.7\pm0.3$ &$6.2\pm1.0$ &$0.54\pm0.27$&$5.0\pm0.2$\\
FSR~923&0.447&&$15.6\pm0.2$&$26.1\pm13.0$&$2.7\pm0.8$&$0.5\pm0.2$ &$4.0\pm1.0$ &$1.12\pm0.42$&$8.9\pm0.5$\\
FSR~932&0.444&&$15.8\pm0.2$&$45.1\pm15.2$&$3.9\pm1.0$&$0.4\pm0.1$ &$3.0\pm0.5$ &$0.79\pm0.20$&$6.7\pm1.1$\\
FSR~942&0.900&&$2.8\pm0.1$&$9.9\pm2.5$&$4.6\pm0.9$&$1.1\pm0.2$ &$8.0\pm1.5$ &$1.25\pm0.24$&$8.9\pm1.7$ \\
FSR~948&0.831&&$3.3\pm0.1$&$10.2\pm5.1$&$4.1\pm1.6$&$0.4\pm0.2$ &$4.2\pm0.5$ &$0.50\pm0.34$&$5.0\pm0.4$\\
FSR~974&0.748&&$6.0\pm0.1$&$11.1\pm6.0$&$3.0\pm1.2$&$0.5\pm0.3$ &$9.0\pm1.0$ &$0.71\pm0.39$&$12.0\pm2.0$\\
\hline
\end{tabular}}
\medskip
 $(\dagger)$: FSR~1644; $(\ddagger)$: FSR~1723. Column~2: arcmin to parsec scale. To minimise degrees of freedom in RDP fits with the King-like profile (see text), $\sigma_{\rm bg}$ was kept fixed (measured in the respective comparison fields) while $\sigma_0$ and \rc\ were allowed to vary. Column~5: cluster/background density contrast ($\delta_{\rm c}=1+\sigma_0/\sigma_{\rm bg}$), measured in colour--magnitude filtered RDPs.
\end{table}