\begin{table}%t2
\caption{Comparison of the FITS coordinate keywords in the old and new system, for
helioprojective-cartesian coordinates in the {\tt TAN}~projection.  The phrase
"exactly the same'' assumes that the same units are used in both cases.  See
Sect.~\ref{other_angular} for a~discussion of angular units.  Although {\tt
CUNIT$i$} did not appear in the original \citet{wells81} paper, it has been
commonly used.}
\label{old_vs_new}
%\centering
\par
\begin{tabular}{lll}
\hline \hline
Keyword		& Original	& WCS\\
\hline
{\tt CRPIX$j$}	& \multicolumn{2}{l}{Exactly the same in both systems}\\
{\tt CRVAL$i$}	& \multicolumn{2}{l}{Exactly the same in both systems}\\
{\tt CDELT$i$}	& \multicolumn{2}{l}{Exactly the same in both systems}\\
{\tt CROTA$i$}	& Rotation angle&
Deprecated
\\
{\tt PC$i$\_$j$}& Not used	& Replaces {\tt CROTA$i$}\\
{\tt CUNIT$i$}	& \multicolumn{2}{l}{Exactly the same in both systems}\\
{\tt CTYPE$i$}	& {\tt SOLARX}	& {\tt HPLN-TAN}\\
		& {\tt SOLARY}	& {\tt HPLT-TAN}\\
\hline
\end{tabular}
\end{table}