\begin{table}%t1
\caption{\label{tab_obs}Observational conditions of the TNOs and Centaurs spectroscopically investigated. }
\small%\centerline
{
\begin{tabular}{lllccccclc} 
\hline\hline
{\bf  Object} & {\bf Date} & {\bf UT} &  {\boldmath{$\Delta$}} & {{\boldmath $r$}} & {\boldmath $\alpha$} &{\bf $T$\boldmath{$_{\rm exp}$}} & {\bf airm.} & {\bf Solar An. (airm.)} & {\bf Slope} \\ 
& & &   {\bf [AU]} & {\bf [AU]} &  {\boldmath [$^{\circ}$]} & {\bf [s]} &  & & {\bf [\%/(\boldmath{$10^{3}$~\AA)}]} \\
 \hline
{\em CENTAURS} & & & & & & & & & \\ 
5145 Pholus        & 2008 Apr. 12  & 05:57:44 & 21.214 & 21.864 & 2.0 & 2600 & 1.21 & Ld102$-$1081 (1.15) &  48.6~$\pm$~0.7 \\
10199 Chariklo     & 2008 Feb. 04  & 07:57:47 & 13.301 & 13.395 & 4.2 & 900 & 1.10 & Ld102$-$1081 (1.13)  &  10.4~$\pm$~0.6 \\
52872 Okyrhoe      & 2008 Feb. 04  & 06:33:30 &  4.879 &  5.800 & 3.8 & 1800 & 1.14 & Ld102$-$1081 (1.13)  &  13.4~$\pm$~0.6\\
55576 Amycus       & 2008 Apr. 12  & 03:43:14 & 15.206 & 16.056 & 2.0 & 2400 & 1.16 & Ld102$-$1081 (1.15)  &  37.1~$\pm$~0.9 \\
{\bf 120061 (2003 CO1)}  & 2008 Apr. 12  & 04:48:44 & 10.180 & 11.122 & 1.8 & 2400 & 1.13 & Ld102$-$1081 (1.15)  &  9.4~$\pm$~0.6  \\
{\bf 2002 KY14}          & 2008 Sep. 21 & 01:11:40 &  7.802 &  8.649 & 3.8 & 1200 & 1.25 & Ld112$-$1233(1.12)   & 36.9~$\pm$~0.7  \\
{\bf 2007 UM126}         & 2008 Sep. 21 & 04:46:01 & 10.202 & 11.163 & 1.6 & 2400 & 1.10 & Ld112$-$1233(1.12)   &  8.8~$\pm$~0.7 \\ 
{\bf 2007 VH305}         & 2008 Nov. 22  & 02:38:07 &  7.853 &  8.638 & 4.2 & 2400 & 1.18 & Ld98$-$978 (1.20)   & 12.1~$\pm$~0.7 \\
{\bf 2008 FC76}          & 2008 Sep. 21 & 00:21:29 & 10.976 & 11.688 & 3.6 & 1800 & 1.29 & Ld112$-$1233(1.12)   & 36.0~$\pm$~0.7 \\
{\bf 2008 SJ236}         & 2008 Nov. 22  & 00:53:58 &  5.522 &  6.364 & 5.0 & 4000 & 1.28 & Ld93$-$101 (1.30)   & 20.9~$\pm$~0.8 \\ \hline
{\em CLASSICALS} & & & & & & & & & \\ 
{\bf 20000 Varuna}       & 2007 Dec. 04  & 06:41:41 & 42.606 & 43.392 & 0.8 & 2400 & 1.57 & Hyades64 (1.41)      &  24.9~$\pm$~0.6     \\
120178 (2003 OP32) & 2008 Sep. 21 & 02:26:48 & 40.545 & 41.365 & 0.8 & 2400 & 1.14 & Ld112$-$1233(1.12)   &  0.9~$\pm$~0.7  \\ 
{\bf 120348 (2004 TY364) }& 2008 Nov. 22  & 04:53:01 & 38.839 & 39.591 & 0.9 & 2400 & 1.27 & Ld93$-$101 (1.30)   & 22.9~$\pm$~0.7 \\
{\bf 144897 (2004 UX10)} & 2007 Dec. 04  & 01:10:32 & 38.144 & 38.836 & 1.0 & 2400 & 1.13 & HD1368 (1.12)        &  20.7~$\pm$~0.8  \\
{\bf 144897 (2004 UX10)} & 2007 Dec. 05  & 02:41:59 & 38.158 & 38.836 & 1.1 & 2400 & 1.19 & Ld93101 (1.24)       &  19.2~$\pm$~0.9  \\
145453 (2005 RR43) & 2007 Dec. 04  & 02:59:10 & 37.623 & 38.511 & 0.6 & 2400 & 1.12 & HD1368 (1.12)        &   1.6~$\pm$~0.6   \\ 
{\bf 174567 (2003 MW12)} & 2008 Apr. 12  & 07:17:41 & 47.318 & 47.968 & 0.9 & 3700 & 1.09 & Ld102$-$1081 (1.10)  &  19.2~$\pm$~0.6 \\ \hline
{\em RESONANTS} & & & & & & & & & \\
{\bf 42301 (2001 UR163)}  & 2007 Dec. 05  & 01:10:23 & 49.625 & 50.308 & 0.8 & 2400 & 1.23 & Ld93$-$101 (1.24)    &  50.9~$\pm$~0.7     \\
55638 (2002 VE95)  & 2007 Dec. 05  & 04:13:26 & 27.297 & 28.248 & 0.5 & 2400 & 1.21 & Ld93$-$101 (1.24)    &  40.0~$\pm$~0.7      \\
90482 Orcus        & 2008 Feb. 04  & 05:25:24 & 46.901 & 47.807 & 0.5 & 2400 & 1.07 & Ld102$-$1081 (1.11)  &   1.6~$\pm$~0.6  \\
208996 (2003 AZ84) & 2008 Nov. 22  & 06:29:23 & 44.883 & 45.458 & 1.0 & 2800 & 1.30 & Ld93$-$101 (1.30)   & 3.6~$\pm$~0.6 \\ 
{\bf 2003 UZ413}         & 2007 Dec. 04  & 04:42:24 & 41.171 & 42.004 & 0.7 & 2400 & 1.36 & Hyades64 (1.41)      &   6.2~$\pm$~0.6  \\
{\bf 2003 UZ413}         & 2008 Sep. 21 & 05:46:16 & 41.469 & 42.163 & 1.0 & 2400 & 1.25 & Ld112$-$1233(1.12)   &  5.0~$\pm$~0.8  \\ 
{\bf 2003 UZ413}         & 2008 Nov. 22  & 03:49:31 & 41.275 & 42.197 & 0.5 & 2400 & 1.15 & Ld98$-$978 (1.17)   & 4.9~$\pm$~0.7 \\ \hline
{\em SDOs} & & & & & & & & & \\ 
42355 Typhon       & 2008 Apr. 12  & 01:07:02 & 16.892 & 17.650 & 2.2 & 1200 & 1.22 & Ld102$-$1081 (1.15)  &  12.1~$\pm$~0.8 \\
44594 (1999 OX3)   & 2008 Sep. 21 & 03:22:39 & 22.023 & 22.889 & 1.3 & 2400 & 1.07 & Ld110$-$361 (1.10)   & 36.2~$\pm$~0.8  \\ 
{\bf 73480  (2002 PN34)} & 2007 Nov. 10  & 00:51:51 & 14.893 & 15.344 & 3.3 & 2800 & 1.22 & LD115$-$871 (1.13)   &  15.8~$\pm$~0.7 \\
{\bf 145451 (2005 RM43)} & 2007 Dec. 04  & 04:04:16 & 34.298 & 35.195 & 0.7 & 2400 & 1.15 & HD1368 (1.12)        &   2.2~$\pm$~0.7    \\
{\bf 2007 UK126}         & 2008 Sep. 21 & 08:18:31 & 45.136 & 45.619 & 1.1 & 2400 & 1.07 & Ld112$-$1233(1.12)   & 19.6~$\pm$~0.7 \\ \hline
{\em DETACHED OBJECTS} & & & & & & & & & \\ 
90377 Sedna        & 2008 Sep. 21 & 06:53:28 & 87.419 & 88.015 & 0.5 & 3600 & 1.20 & Ld112$-$1233(1.12)   & 40.2~$\pm$~0.9 \\
120132 (2003 FY128)& 2008 Apr. 12  & 02:32:57 & 37.477 & 38.454 & 0.3 & 2800 & 1.06 & Ld102$-$1081 (1.10)  &  26.7~$\pm$~1.0  \\ \hline
\end{tabular} 
}
\smallskip
 Observational conditions: for each object we report the observational date and universal time (UT of the beginning of the
exposure), the geocentric distance ($\Delta$), the heliocentric distance ($r$), the phase angle ($\alpha$), 
the total exposure time, the airmass (mean of the airmass value at the beginning and
at the end of observation), the observed solar analogue stars with their airmass used
to remove the solar contribution, and the spectral slope value computed in the 0.5$-$0.8~$\mu$m range. The TNOs and Centaurs observed in spectroscopy for the first time are in bold. 
\end{table}