WE WERE TALKING ABOUT THE SUN!!!!!
Well the topic of this thread was about the moon. So I decided to focus on light's effect on the moon.
In the case of the sun, light would originate within the Sun's core and have to travel through it's own hydrogen chromosphere and photosphere. After this the light must travel towards the earth.
Since, in the place of gravity we have acceleration, the parabolic mirror effect could be analogous to trailing your finger through calm water. Your finger would be the sun, and the water's wake would be the shape of light distortion. Whatever is following behind your finger, in this case the earth, would see the area near the finger in a convexed shape.
Simply extrapolate this effect to a three dimensional environment, perhaps imagining a ball traveling through water, and you have a convincing argument for the spotlight effect.