Dynamics and Physics of Bodies of the Solar System Russian The angles of aberration of plasma tail axes from direction of prolonged radius-vector of the comets С/2001 Q4 (NEAT) and C/2004 Q2 (Machholz) are calculated. The values were used to obtain the radial component of solar wind velocity in May 2004 and in January— February 2005. The values of solar wind velocity obtained from the comet aberration angles and from satellite data are compared. Possible causes of disagreement between the values obtained are discussed. plasma tail,comet