\begin{table}%t1 \caption{\label{ch3_mosaic_info.tab}Characteristics of the GEMINI data set. Observing dates and times are given for each of the 12~h observing runs, which have been indicated by their shortest baseline length. We calculated the conversion factor between mJy/beam and K at 345~MHz, the average of the $\lambda^2$~sampling of the (usable) frequency channels in our data set.} %\centering \small \begin{tabular}{lcccccc} \hline\hline Central position & \multicolumn{6}{l}{ ($\alpha,\delta$)$_{{\rm 2000}}$ = (109\degr, 36.5\degr); ($l,b$) = (181\degr, 20\degr) } \\ Mosaic size & \multicolumn{6}{l}{9\degr\ $\times$ 9\degr} \\ Pointings & \multicolumn{6}{l}{7 $\times$ 7}\\ Frequencies & \multicolumn{6}{l}{324--387 MHz} \\ & \multicolumn{6}{l}{202 independent frequency channels (Hamming taper)} \\ Resolution & \multicolumn{6}{l}{2.76\arcmin\ $\times$ 4.70\arcmin} \\ Stokes $V$ noise level & \multicolumn{6}{l}{6.2 mJy (2.0 K)} \\ $\mathcal{R}$\ noise level & \multicolumn{6}{l}{0.5 mJy (0.14 K)} \\ Conversion Jy--K & \multicolumn{6}{l}{1 mJy/beam = 0.32 K (at 345 MHz)} \\ \hline Shortest baseline (m) & 36 & 48 & 60 & 72 & 84 & 96 \\ Observing date & \hspace{-1mm}03/01/17\hspace{-1mm} & \hspace{-1mm}03/01/21\hspace{-1mm} & \hspace{-1mm}02/12/18\hspace{-1mm} & \hspace{-1mm}02/12/05\hspace{-1mm} & \hspace{-1mm}03/01/22\hspace{-1mm} & \hspace{-1mm}03/01/13\hspace{-1mm} \\ \hspace{3mm} (yy/mm/dd) \\ Start time (UT) & 17:04 & 16:37 & 18:45 & 19:36 & 16:39 & 17:32 \\ End time (UT) & 05:04 & 04:36 & 06:43 & 07:34 & 04:37 & 05:31 \\ \hline \end{tabular} \end{table}