Let the image of the point (5/3, 5/3, 8/3) in the plane x-2 y+z-2=0 be P. If the distance of the point Q(6,-2, α), α>0, from P is 13, then α is equal…

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