Figure 6: The angle of wave tilt (wave rotation) determined for and axes by analyzing the vortex triplets geometry. The expected values were 2.5 second of arc through -axis and 0 second of arc through -axes. In this example, around 350 vortices were observed at the image area. The statistics were made for 3500 triplets. Probability density function can be described by the Lorentz distribution (when using cells instead of triplets, we get the Gaussian distribution).