3d Geometry

Let the image of the point \(\left(\frac{5}{3}, \frac{5}{3}, \frac{8}{3}\right)\) in the plane \(x-2 y+z-2=0\) be P. If the distance of the point \(Q(6,-2, \alpha), \alpha > 0\), from \(\mathrm{P}\) is 13 , then \(\alpha\) is equal to ___________.