\begin{table}%t5
\caption{\label{tab:grid_observations}Grid field observations and MegaCam/MegaPrime optical \mbox{improvements}.}
\small%\centering
\par
\begin{tabular}{cccc}
\hline
\hline
Semester & Date       & Field  & Band \\
\hline
\multirow{3}{0.75cm}{2003B} 
 & 2003-10-02 & Grid-2 & $\rme\ime$    \\
 & 2003-10-23 & Grid-2 & $\ume\gme\zme$   \\
 & 2003-10-24 & Grid-2 & $\ime \rme$    \\
\hline
\multirow{3}{0.75cm}{2004A} 
 & 2004-02-25 & \multicolumn{2}{c}{\em light baffle installed} \\
 & 2004-03-19 & Grid-1 & $\ume \gme \rme \ime \zme$ \\
\hline
\multirow{3}{0.75cm}{2004B} 
 & 2004-12-03 & \multicolumn{2}{c}{\em L3 Lens flipped upside-down} \\
 & 2004-12-03 & Grid-1 & $\gme \rme \ime$   \\
 & 2004-12-11 & Grid-1 & $\ume \gme \zme$   \\
\hline
\multirow{1}{0.75cm}{2004A} 
 & 2005-07-20 & \multicolumn{2}{c}{\em  Spacer moved (5.5 mm to 2.1 mm)} \\
\hline
\multirow{2}{0.75cm}{2005B} 
 & 2005-09-20 & \multicolumn{2}{c}{\em Focal plane tilt tweaked} \\
 & 2005-10-10 & Grid-2 & $\ume \gme \rme \ime \zme$ \\
\hline
\multirow{5}{0.75cm}{2006B} 
 & 2006-09-13 & Grid-2 & $\ime$ \\
 & 2006-09-14 & Grid-2 & $\rme$ \\
 & 2006-09-15 & Grid-2 & $\zme$ \\
 & 2006-09-16 & Grid-2 & $\ume$ \\
 & 2006-09-19 & Grid-2 & $\gme$ \\
\hline
\multirow{4}{0.75cm}{2007A} 
 & 2007-03-21 & Grid-1 & $\rme$ \\
 & 2007-03-22 & Grid-1 & $\ume \gme$ \\
 & 2007-03-23 & Grid-1 & $\ime$ \\
 & 2007-03-24 & Grid-1 & $\zme$ \\
\hline
\multirow{4}{0.75cm}{2007B} 
 & 2007-10-18 & Grid-1 & ${\ime}_2$ \\
 & 2007-11-08 & Grid-1 & ${\ime}_2$ \\
 & 2007-11-11 & Grid-1 & $\rme$ \\
 & 2007-11-12 & Grid-1 & $\gme$ \\
\hline
\end{tabular}
\end{table}