[MIham] SUNSPOT MIRAGE

[Frank]

SUNSPOT MIRAGE: For many photographers, departing sunspot AR2529 was an 
irresistible target at sunset. The sunspot's heart-shaped core beamed 
through the rosy twilight, marking the sun for a unique shot. On April 
16th in San Francisco, California, it got a little weird.

"Both the sun and the sunspot were stretched and distorted as the sun 
sank behind the waves of the Pacific Ocean," says Mila Zinkova. "Notice 
the vertical stretching of the sunspot. It was amazing to watch how the 
appearance of the sun changed as the sunset progressed." Here is the 
full video: https://www.youtube.com/watch?v=zIQj7Jwvg84 
<https://www.youtube.com/watch?v=zIQj7Jwvg84>

Atmospheric optics expert Les Cowley explains what happened: "Each 
sunspot on Mila's picture is from a mini mirage. The California Coast is 
famous for its temperature inversions. Air cooled by the offshore ocean 
current lies beneath warm air from inland. Sunset sunlight between the 
layers bends and splits into three mirage images. Two sun slices descend 
and one upside-down one rises. Nature is not always so simple though. In 
Mila's case, there were multiple small inversion layers. Each inversion 
layer sliced up the sun like the corrugations of a Chinese lantern. If 
the air were steady enough we might see that some of the heart shaped 
sunspots were upside down."

Today, AR2529 has left the disk of the sun. Good-bye, and thanks for all 
the photo-ops.