  Breaking the chiral symmetry, rotation induces a secondary Hopf bifurcation
in weakly nonlinear hexagon patterns which gives rise to oscillating hexagons.
We study the stability of the oscillating hexagons using three coupled
Ginzburg-Landau equations. Close to the bifurcation point we derive reduced
equations for the amplitude of the oscillation, coupled to the phase of the
underlying hexagons. Within these equation we identify two types of long-wave
instabilities and study the ensuing dynamics using numerical simulations of the
three coupled Ginzburg-Landau equations.
