# What is an "exquisitely rare pollen corona"? How can pollen produce several tight rainbow circles around the Sun, and why pollen specifically?

The Forrest Mims YouTube video An Exquisitely Rare Pollen Corona shows a pair of rings closely circled around the Sun with rainbow colors; blue on the inside.

The first annulus is easy to see, the second is faint so I've played with the color and contrast to bring out the red part to contrast with the blue sky.

Question: What is an "exquisitely rare pollen corona"? How can pollen produce several tight rainbow circles around the Sun, and why pollen specifically?

• In fact, it's not "exquisitely rare": I see pollen coronas like this yearly since having first noticed one — in first weeks of June at 60°N 30°E. Jul 20 at 16:02