# Why is my entire document rotated by 90 without \begin{landscape}

Why my entire document was rotated by 90 degrees when I used \usepackage{lscape}, even though without \begin{landscape} and \end{landscape}

\documentclass{aastex63}
\usepackage{graphicx}
\usepackage{subfigure}
\usepackage{booktabs}
\usepackage{lineno}
\usepackage{longtable}
\usepackage{lscape}

\begin{document}
\centering
my text
\begin{longtable}{cccccccccccccc}
\caption{my title}
\caption{countinue}

• Presumably you added lscape because you wanted to rotate the longtable. If so, you might want to take a look as the deluxetable environment that comes with aastex: "There is support in the AASTeX package for tables via two mechanisms: LATEX’s standard table environment, and the deluxetable environment, which allows for the formatting of lengthy tabular material. Tables may be marked up using either mechanism, although use of deluxetable is preferred." According to the user guide, deluxetable also offers pagebreaks and rotation. – leandriis Jan 26 '20 at 18:25