  \subsection{Standard Reference Position (StdRefPos)}
  \label{sect:StdRefPos}

  \textbf{BaseURL}:  http://www.ivoa.net/rdf \newline
  \textbf{Vocabulary}: refposition \newline

  We include here the initial Standard Reference Position Vocabulary.  The formal list is stored and maintained as a controlled vocabulary external to this document at the URL listed above.  The URI for each term is built as <BaseURL>/<Vocabulary>/<Term>, where Term is one of:

  \small
  \begin{itemize}
    \item[\textbf{TOPOCENTER}]: "Local"; in most cases this will mean: The location of the telescope.
    \item[\textbf{BARYCENTER}]: Center of the solar system barycenter
    \item[\textbf{HELIOCENTER}]: Center of the sun.
    \item[\textbf{GEOCENTER}]: Center of the Earth.
    \item[\textbf{EMBARYCENTER}]: Earth-moon barycenter
    \item[\textbf{UNKNOWN}]: Unknown reference position. \newline Only to be used as a last resort. The client is responsible for assigning a suitable default.
  \end{itemize}
  \normalsize
