形似希腊字母Ω的东升旭日

2020年9月21日

Omega Sunrise
Image Credit & Copyright: Juan Antonio Sendra

Explanation: Capturing this sunrise required both luck and timing. First and foremost, precise timing was needed to capture a sailboat crossing right in front of a rising Sun. Additionally, by a lucky coincidence, the background Sun itself appears unusual — it looks like the Greek letter Omega (Ω). In reality, the Sun remained its circular self — the Omega illusion was created by sunlight refracting through warm air just above the water. Optically, the feet of the capital Omega are actually an inverted image of the Sun region just above it. Although somewhat rare, optical effects caused by the Earth’s atmosphere can make distant objects near the horizon — including the Sun and Moon — look quite unusual. This single exposure image was taken over the Mediterranean Sea just over two weeks ago near Valencia, Spain.

Tomorrow’s picture: equal sun arcs

形似希腊字母Ω的东升旭日
影像提供与版权: Juan Antonio Sendra

说明: 要拍下这种日出景象，运气和计时精准缺一不可。首先，快门时间要抓得非常精准，才能捕捉到帆船穿过东升的旭日前方。此外运气特佳，背景太阳的形状恰好又很特殊，形似希腊字母Ω（欧米伽）。事实上，日盘的形状仍是浑圆的，其Ω形纯是阳光受到水面上方的热空气之折射所致。从影像来说，大写字母Ω的底部，其实是近海面太阳盘面的光学反转。这种现象虽然有些罕见，但地球大气的光学效应，的确会让悬在地平线附近遥远天体（包括太阳和月亮）的外观变得颇不寻常。这张单曝光影像记录的景象，是在2星期之前，出现在西班牙．瓦伦西亚市附近的地中海面上。

明日的图片: equal sun arcs