Trouble getting table centered

Question

I'm using the aastex document class (trying to get a table done in the Astrophysical Journal format) and I have this table I'm trying to produce but it keeps getting right justified almost to the point of cutting off the table. I'm not sure how to fix this and I've tried a few things I've found on Google to no benefit. Here's my (shortened code):

\documentclass{aastex}
\usepackage{longtable}
\begin{document}

\begin{center}
\begin{longtable}{c|c|c|c|c|c|c|c|c|c|c}
\caption{NGC2264 Protostars}\\
\hline
\multicolumn{1}{c}{Name} & \multicolumn{1}{c}{RA} & \multicolumn{1}{c}{DEC} &     \multicolumn{1}{c}{Mean I1} & \multicolumn{1}{c}{Mean I2} & \multicolumn{1}{c}{Alpha K2} & \multicolumn{1}{c}{Class} & \multicolumn{1}{c}{Alpha K8} & \multicolumn{1}{c}{Av} & \multicolumn{1}{c}{Avg Av}\\
\hline
\hline
Mon-000101 & 100.27242 & 9.608597 & 11.082 & 10.034 & 0.39  & I     & 0.39  & 31.1  & 31.1 \\
Mon-000171 & 100.2923 & 9.52286 & 14.834 & 14.385 & 0.45  & I     & 0.45  & 33.7  & 33.7 \\
Mon-000174 & 100.27621 & 9.563802 & 11.605 & 10.134 & 0.95  & I     & 1.29  & 30.8  & 30.8 \\
Mon-000191 & 100.28709 & 9.495832 & 9.231 & 8.105 & 1     & I     & 1.01  & 0     & 0 \\
Mon-000323 & 100.25761 & 9.576176 & 9.385 & 8.513 & 0.31  & I     & 0.04  & 16.8  & 16.8 \\
\end{longtable}
\end{center}
\end{document}

Lookin' for some pointers. Thank you.

Answer 1

Your table is centered, but too wide (horizontally). In *.log file we can find

Overfull \hbox (79.52667pt too wide) in alignment at lines 6--17

This is over 1.1 inch. You should make your table thinner to notice the effect of centering. For example, the following changes (I don't know, if acceptable) make your table not too wide. (Additional text to show the text width).

\documentclass{aastex}
\usepackage{longtable}
\begin{document}

\overfullrule5pt

{\tiny
Some text. Some text. Some text. Some text. Some text. Some text. Some text, text. 
Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. 
Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. 
Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. 
Some text. Some text. Some text. Some text. Some text. Some text. Some text. Some text. 
}

\begin{center}
\begin{longtable}{c|c|c|c|c|c|c|c|c|c|c}
\caption{NGC2264 Protostars}\\
\hline
\multicolumn{1}{c}{Name} & \multicolumn{1}{c}{RA} & \multicolumn{1}{c}{DEC} &     \multicolumn{1}{c}{Mean I1} & \multicolumn{1}{c}{Mean I2} & \multicolumn{1}{c}{$\alpha$ K2} & \multicolumn{1}{c}{Class} & \multicolumn{1}{c}{$\alpha$ K8} & \multicolumn{1}{c}{Av} & \multicolumn{1}{c}{Avg Av}\\
\hline
\hline
101 & 100.27242 & 9.608597 & 11.082 & 10.034 & 0.39  & I     & 0.39  & 31.1  & 31.1 \\
171 & 100.2923 & 9.52286 & 14.834 & 14.385 & 0.45  & I     & 0.45  & 33.7  & 33.7 \\
174 & 100.27621 & 9.563802 & 11.605 & 10.134 & 0.95  & I     & 1.29  & 30.8  & 30.8 \\
191 & 100.28709 & 9.495832 & 9.231 & 8.105 & 1     & I     & 1.01  & 0     & 0 \\
323 & 100.25761 & 9.576176 & 9.385 & 8.513 & 0.31  & I     & 0.04  & 16.8  & 16.8 \\
\end{longtable}
\end{center}

\end{document}