Aureole of the Sun's optical corona

Seen from Earth, the Sun subtends an angle of 0.5 degrees. A little finger at arm's length subtends 1 degree. In the picture above, as the sunlight passes through thin high cloud the light is spread. It subtends about 4 degrees. This is an optical corona rather than the halo that I saw a couple of week's ago. This time the diffraction is through water droplets rather than ice. I saw only the central bright spot up to the first minimum which is called the aureole. Full pictures can be seen here https://en.wikipedia.org/wiki/Corona_(optical_phenomenon) I need to find out if the aureole is basically the same as the Airy disc that you see when light is diffracted through an aperture and then to work out how a hole and a collection of water droplets can produce the same pattern.