The stunning spectacle of rare rainbow-coloured rings appearing around the sun last week was spotted by some excited community members in the region.

The optical phenomenon, known as ‘pollen corona’ occurs when the Sun is partially obscured and light hits a swarm of pollen, resulting in a scattering of wavelengths and diffraction patterns.

The pastel-coloured halo was the result of a mass release of pollen exploding from Pilliga pine trees and blanketing the air as far as Mudgee on Tuesday, 27 August and captured in some stunning photographs.

Coonabarabran resident Shona Rankin, below, snapped a perfect image. She says that the colours of the corona caught her eye when she was hanging out the washing.

“I make a point of trying to avoid the glare of the sun but I noticed that there was a very interesting glare; my children spotted at the same time,” she said.  “I looked up and it was wow! As the colours developed, I just took more and more photos as the rainbow circles got larger.

“I was just amazed and astonished the whole time; I literally couldn't believe it. It was just beautiful; we were all taking photos.  

“I popped one of my shots up on Facebook for comment and it has since become a bit of a talking point.

“I know a little bit about light refraction, but always thought the best time to see something like this was at night with a telescope. I have never ever seen anything like it before. I was completely astounded by the colour and how it progressively started getting bigger and bigger; it was just magical.”

As everyone would be aware, looking directly at the sun can cause permanent eye damage, but Shona’s images were successful because they were taken with shadow falling across the sun. Similarly, Wendy Abberton’s photographs are just as impressive.

“All I can say about what I saw on Tuesday afternoon was that I thought something was seriously wrong with my vision!” she explained. “I was dragging the rubbish bin up from the road and the light seemed different. I was surprised to see a circular rainbow around the sun filtering through the trees. Having little faith in my own eyes, I took a couple of photos with my phone and was surprised by what I saw.

“Now I know what it was, I am delighted that I saw it and photographed it. It was a special moment for me.”

Perfect conditions in alignment

Coonabarabran weather guru, Peter Brookhouse says that to witness a pollen corona in all its glory, specific conditions must align harmoniously.

“A significant concentration of pollen particles must be present in the air and the weather needs to be warm, dry, calm and clear,” Peter explained. “These were the perfect conditions last week for the pollen corona to form.

“There was a mass release of pollen from the Cypress Pine. An anecdotal story from a helicopter pilot is that he thought he saw smoke which he followed but it was coming from a tree and then he realised that it was a release of pollen.

“Pilliga Cypress pines have female and male cones, which are wind pollinated. The pollen is carried in the lower atmosphere, so we are looking at the sun through a layer of air which is laden with pollen; a pollen haze.

“You don't need high wind to make the pollen disperse. As we know, warm air from the ground rises; it will rise to a certain level on a fine day and you’ve got an inversion. It's not going to go to an immense height.  It might go to maybe a thousand metres or 1,500 metres and it's mixing the pollen throughout the lower layer of the atmosphere," he said.

Apparently, the smaller the pollen grains the bigger the corona. 

“The other thing is that the irregular shape of the pollen helps it to be moved by air currents and, because they are floating, they all tend to orientate similarly and it is this aerodynamics cause the refraction patterns and scattering that forms the corona.

“The first time I saw a pollen corona was four years ago. I was sitting on the deck and the sun was partly obscured, which you need otherwise you're blinded by sunlight. Later in the day, walking through filtered light under a tree canopy, each pinhole of light was a rainbow and was casting rainbows on the ground as well.

“When you look at these photos what you can see is the spectrum of rainbow colours that is repeated and repeated. Once I saw the photographs, I knew what they were of straight away and I am really disappointed that I missed the event.

“It's quite impressive and a very interesting phenomenon that can occur annually depending on the variability of the seasons.”

Perfect conditions - Wendy Abberton’s pollen corona image . Supplied.