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tokens: to give a more reliable answer on the issue of zero point of the v sin i data. On the other hand, by checking other (even though sparse and, in general, less accurate) data sources on Praesepe ( Cummings et al. 2017 ; Quinn et al. 2012 ; Pace Pasquini 2004 ; Boesgaard et al. 2004 ; Rachford 1998 ; Malavolta et al. 2016 ; Mann et al. 2017 ) we find that most of the published values (~ 80%) are an average of 10–20% higher than our values. Therefore, we think that the current data lend support to a non-isotropic inclination angle distribution rather than to the isotropic one. Fig. 4 Observed cumulative distributions of sin i and the associated model distributions assuming isotropic and cone distributions (see Jackson et al. 2010 ) for the inclination angle. See Table 3 for the ( α , λ ) parameters used in the cone distributions. The error bars correspond to 1 σ limits derived from the random simulations of the theoretical CDFs. To avoid crowding, we show them only for the isotropic distributions because the errors for the cone distributions are very similar. For the other datasets we see a comfortable overall consistency between the expected distributions and the best fitting models. The optimal cone models (with large parameter scatter, as expected) are indistinguishable from the isotropic model for all field star samples, although there is a slight indication for the underestimation of the observational noise for Field (C): the observed CDF is shallower than that of the isotropic distribution. The opposite is likely to be true for the planetary host samples, especially for the KOI sample. We find that decreasing the noise on v sin i by a factor of two (relative to the values given by Winn et al. 2017 ), the fit improves substantially with σ cone = 0.028 ± 0.008 and cone parameters α = 80 ° ± 11 ° and λ = 27 ° ± 18 ° . These cone parameters may imply the presence of some oblique systems in the KOI sample. Instead of making any far-reaching conclusion of this sort from this test alone, we refer to Hirano et al. (2014) and Winn et al. (2017) for further discussion of the topic. However, we draw attention to the importance of proper noise estimation when modeling the distribution of the inclination angles from spectroscopic rotation velocities. 5 Conclusions By using recently determined stellar rotation periods, available spectroscopic rotation velocities, and evolutionary stellar radii based on IRFM-calibrated effective temperatures, we derived the distribution of the line-of-sight inclination angles from 113 main sequence F − K stars in the Praesepe open cluster. With the aid of statistical modeling, we found signatures of a broad rotational axis alignment. The cone model of Jackson et al. (2010) yielded an overall cone axis angle of 76 ° ± 14 ° and an opening angle of 47 ° ± 24 ° . Isotropic angle distribution is far less likely, except when the spectroscopic rotational velocities used in this work are systematically overestimated. Although we