Big circle around the Moon

Two days before in Chennai, we were able to see a big circle around the moon, and it become the talk of the city. I managed to take a snap of the sky with the moon and the circle. But the circle is cut at the top and the bottom. And when I saw the snap in my camera, the circle was visible. But when I put that in my laptop, I am not able to see anything. So I used photoshop to change the color, brightness properties to show the circle very slightly. The next morning, newspaper THE HINDU had the snapshot which is really good (of course they have a better camera than me, lol).

The ring is caused by conditions that are similar to appearance of rainbow. The rainbow is formed when light from sun passes through water droplets in the atmosphere and are split into colors like when a light passes through a prism. These rays are reflected from the other side of the droplet and what we see is the rainbow. Similarly here the circle is formed by refraction of moon light (light from sun reflected by moon) from ice crystals in the atmosphere.