Spectral Line Selection in the ALMA Observing Tool

The Atacama Large Millimetre / submillimetre Array (ALMA) is the world's most powerful ground-based telescope, offering views of the mm/submm universe with unparalleled spatial and spectral resolution. With the high level of flexibility offered by ALMA, proposals making full use of its capabilities are complex and it would be easy for an inexperienced radio astronomer to request an invalid instrument configuration. In this paper we describe the hardware-aware filters and real-time filtering techniques used by the ALMA Observing Tool (OT) that lets astronomers efficiently identify their primary target lines and 'lines of opportunity', all the while preventing the user from constructing invalid proposals.