Smoothed normalized profile of He line at 6678 Å (left) and normalized amplitude of Fourier transform of the same profile (right, solid line). The dotted curve denotes the transform of the rotational broadening profile alone. The first minimum occurs at σ ~ 0.00275 c/Å (vertical dotted line), corresponding to vsini ~ 239.5 km s^-1. Uncertainty on vsini is estimated at around ±10 km s^-1.