The decays $D^{**} \to D^{*+}\pi^-\to D^0\pi^+\pi^-$ are used to measure the helicity angle, i.e. the angle between the two pions in the rest frame of the $D^*$. The decays of $D_1(2420)^0$, $D^*_2(2460)^0$, $D(2550)^0$, $D^*(2600)$, $D(2750)$ were measured. The data were read from the plots in the papers and therefore for the $D_1(2420)^0$, $D^*_2(2460)^0$ the error bars are the size of the points in the plots.