Isabelle 的點滴

K同學分享了一張極漂亮且珍貴的「全圓彩虹」，來自攝影師柯林•萊昂哈特（Colin Leonhardt），介紹文如下：

『This double full-circle rainbow was seen in 2013 from a helicopter over Perth, Australia. (Photo: Colin Leonhardt, Bird's Eye View Photography)

The photo was featured Sept. 30 on NASA's Astronomy Picture of the Day, with this explanation:

"From the ground, typically, only the top portion of a rainbow is visible because directions toward the ground have fewer raindrops. From the air, though, the entire 360 degree circle of a rainbow is more commonly visible."

The image of the full-circle rainbow, with a fainter image outside it, followed the helicopter intact for about five kilometers (about three miles), NASA said.

The Astronomy Picture of the Day is a service of the Astrophysics Science Division at the space agency's Goddard Space Flight Center in Greenbelt, Md., and Michigan Technological University in H0ughton, Mich.

The picture of the day has appeared daily since June 1995.』

(資訊來自：http://www.chron.com/news/science-environment/article/NASA-Picture-of-the-day-captures-helicopter-5806454.php#photo-6966752)