A new rest frequency can now be selecting using the plot units toolbox. The new frequency can be selected by clicking on a position in the plot, or a line identifier.
The TSYS value is now derived from the median effective exposure time when a better estimate is not available.
The alignment of spectra in a plot can now be made to happen via the offset
coordinate system (when spectral origins are defined), and also via the
coordinate system of the current spectrum (rather than via the WAVE system,
this means velocity systems can be aligned directly).
SPLAT-VO -- A VO-enabled Spectral Analysis Tool