\begin{table}%t1
\caption{\label{Table: transitions}Observed transitions.}
\par
%\centering
\par
\begin{tabular}{lrcccc} 
 \hline\hline \noalign{\smallskip}
Species\tablefootmark{a} 	& Frequency	&	Band\tablefootmark{b} & $T_{\rm sys}$\tablefootmark{c}  & $t_{\rm int}$\tablefootmark{d}  &Transition   	\\    
& (GHz) &  & (K) & (s)&   \\
\hline \noalign{\smallskip}
 NH$^+$ & 	1012.540	& 4a &  385 & 47  &   $^2\Pi_{1/2}$  $J$ = 3/2 $\leftarrow$ 1/2    \\
 NH  &	974.478	&	4a & 339 	 &30	& $N = 1\leftarrow0$ $J = 2\leftarrow1$  \\
$o$-NH$_2$	&	952.578	&	3b& 230  & 15& $1_{1,1}$--$0_{0,0}$ \\
$o$-NH$_3$	&	572.498		& 1b  & 83 &276  &  1$_0$--0$_0$   \\
 	&	1214.859	&	5a  & 1012   &49   & 2$_0$--1$_0$   \\
$p$-NH$_3$	 	&	1215.245	 &5a & 1012 & 49	    & 2$_1$--1$_1$   \\
\hline 
\end{tabular}
\tablefoot {\tablefoottext{a}{The NH and NH$_{2}$~frequencies refer  to the strongest hyperfine structure component;} 
\tablefoottext{b}{HIFI consists of 7~different mixer bands and two  double sideband spectrometers. All transitions were observed in the upper sideband except~NH$^+$;}
\tablefoottext{c}{system temperature;}
\tablefoottext{d}{the on-source  time for each integration.}}
\end{table}