= Terrell rotation
{c}
{title2=$\sin\theta=v/c$}
{wiki}
The apparent rotation of a moving object arises when <length contraction> is combined with different light emission times for photons arriving at a camera together. For an edge-on plane lamina moving along x, let X,Y be its rest coordinates and put a distant camera on the negative y axis. Simultaneous reception requires $t+Y/c=\text{constant}$. Since $x=X/\gamma+vt$, its transverse image coordinate is $X/\gamma-\beta Y$. This is the projection of a stationary lamina rotated through $\theta$ with $\cos\theta=1/\gamma$, $\sin\theta=\beta$. It describes a photographic projection; simultaneous laboratory positions retain <length contraction>. The simple angle formula assumes the transverse distant-camera geometry.
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