32 Plane $M$ intersects with plane $N$ at an angle $\theta$, then the orthogonal projection of a circle on plane $M$ onto plane $N$ is an ellipse, its eccentricity equals $\qquad$ .
$32 \sin \theta$. Let the semi-major axis be $a$, then the semi-minor axis $b=a \cos \theta$, so the eccentricity $e=\frac{\sqrt{a^{2}-b^{2}}}{a}=\sin \theta$.