  We consider surface-tension driven convection in a rotating fluid layer. For
nearly insulating boundary conditions we derive a long-wave equation for the
convection planform. Using a Galerkin method and direct numerical simulations
we study the stability of the steady hexagonal patterns with respect to general
side-band instabilities. In the presence of rotation steady and oscillatory
instabilities are identified. One of them leads to stable, homogeneously
oscillating hexagons. For sufficiently large rotation rates the stability
balloon closes, rendering all steady hexagons unstable and leading to
spatio-temporal chaos.
