# Argument of \begin has an extra }

I've been emailed a 'sample' document that I'm supposed to cut/copy/paste to my needs. However, it seems like it's full of problems. The first thing that keeps coming up is:

./testit.tex:9: Argument of \begin has an extra }.


The document:

\documentclass{aastex}
\usepackage{lscape}
\usepackage{longtable}

\begin{document}

\clearpage
\longtable
\begin{landscape}
\begin{deluxetable}{ccccccccccccccc}
\tabletypesize{\scriptsize}
\tablecolumns{10}
\tablewidth{0pt}
\tablecaption{\bf NGC 2264 members monitored with {\em CoRoT} and {\em
Spitzer}}
\colhead{H$\alpha$} & \colhead{Comp?}}
\startdata
CSI Mon-000007 & J06415304+0958028 & 223994721 & 12.22$\pm$0.02 & 11.53$\pm$0.03 & 11.18$\pm$0.02 & 10.12$\pm$0.00 & 9.74$\pm$0.00 & 9.32$\pm$0.00 & 8.75$\pm$0.00 & 6.20$\pm$0.03 & II & K7 & - & Y \\
CSI Mon-000011 & J06411725+0954323 & 223985009 & 12.83$\pm$0.02 & 12.05$\pm$0.03 & 11.55$\pm$0.02 & 10.49$\pm$0.00 & 10.07$\pm$0.00 & 9.69$\pm$0.00 & 8.82$\pm$0.00 & 5.60$\pm$0.01 & II & K7 & 58.30 & N \\
CSI Mon-006491 & J06392550+0931394 & 616920065 & 13.77$\pm$0.03 & 12.86$\pm$0.03 & 12.38$\pm$0.02 & 11.73$\pm$0.00 & 11.44$\pm$0.00 & 11.15$\pm$0.01 & 10.52$\pm$0.01 & 7.86$\pm$0.03 & II & - & - & N
\enddata
\tablecomments{We have assembled a list of NGC~2264 region members,
candidates, and field stars, called the CSI~Mon catalog. Here we
show only the Mon identification numbers of objects discussed in
this paper. The {\em CoRoT} ids are from the SRa05 run. H$\alpha$ refers to the equivalent
width of the H$\alpha$ emission line, and we adopt the values of \citet{2002AJ....123.1528R} and \citet{2005AJ....129..829D}.
Spectral types are from \citet{1956ApJS....2..365W}, \citet{2004AJ....127.2228M},
and \citet{2005AJ....129..829D}, Objects with the disk class II/III
are have a class III SED based on the slope, but have significant
evidence of a weak disk based on their [3.6]-[8.0] colors. The comp''
column denotes whether the object appears to have a companion within
1\arcsec (Y'' if yes). Detection is based on visual binarity or elongation of the
PSF reported by \citet{2009AJ....138.1116S}, or spectroscopic indications of
binarity via variable radial velocity measured by \citet{2006ApJ...648.1090F}.
Objects with no known companion (N'') may still be
undetected binaries. *Objects with IRAC staring data are marked with
asterisks.}
\end{deluxetable}


Why is it saying this? I don't see anything obvious (to me, at least).

• Where is \end{landscape}?? – Sigur Jan 20 '14 at 23:15
• Where is \end{document}?? – cfr Jan 20 '14 at 23:21
• Isn't longtable an environment? – You Jan 20 '14 at 23:22
• what is \begin{deluxetable}? – Rmano Jan 21 '14 at 0:15

Package longtable defines an environment longtable that takes a mandatory argument, the specification for the columns. Thus the following token \begin becomes the argument for \longtable.
Since a table is following \begin{landscape}, the previous \longtable is probably just a typo. If you remove it, the file compiles (after adding \end{landscape} and \end{document}.