The equivalent polar coordinates are:
\(r > 0\): \((8, \frac{\pi}{2})\)
\(r < 0\): \((-8, \frac{3\pi}{2})\)
Thus, we have
\[
\begin{array}{c}
\left(-8, \frac{3 \pi}{2}\right) \\
r>0 \quad(r, \theta)=\left(8, \frac{\pi}{2}\right) \\
r<0 \quad(r, \theta)=\left(-8, \frac{3 \pi}{2}\right)
\end{array}
\]
So the answer is \(\boxed{(-8, \frac{3 \pi}{2})}\).