# Did I see the Formosat-5 F9 2nd stage nozzle vibrate at about 2Hz at SECO-1?

Did I see the F9 2nd stage nozzle vibrate at about 2Hz at SECO-1? It looked like the bottom of the bell vibrated in an elliptical shape. Did I imagine that? Has this happened before?

$\hskip 3.4 cm$It's just after T+ 09:17, playing at half speed:

$\hskip 3.5 cm$

• Watching the video the vibration happens right at SECO and it looks like it is a transient as the engine shuts down. – geoffc Aug 24 '17 at 19:21