落日的多重绿闪

2023年3月28日

A Multiple Green Flash Sunset
Image Credit & Copyright: T. Slovinský & P. Horálek (IoP Opava); CTIO, NOIRLab, NSF, AURA

Explanation: Yes, but can your green flash do this? A green flash at sunset is a rare event that many Sun watchers pride themselves on having seen. Once thought to be a myth, a green flash is now understood to occur when the Earth’s atmosphere acts like both a prism and a lens. Different atmospheric layers create altitude-variable refraction that takes light from the top of the Sun and disperses its colors, creates two images, and magnifies it in just the right way to make a thin sliver appear green just before it disappears. Pictured, though, is an even more unusual sunset. From the high-altitude Cerro Tololo Inter-American Observatory in Chile one day last April, the Sun was captured setting beyond an atmosphere with multiple distinct thermal layers, creating several mock images of the Sun. This time and from this location, many of those layers produced a green flash simultaneously. Just seconds after this multiple-green-flash event was caught by two well-surprised astrophotographers, the Sun set below the clouds.

Tomorrow’s picture: dolphin vs cloud

落日的多重绿闪
图像提供与版权: T. Slovinský & P. Horálek (IoP Opava); CTIO, NOIRLab, NSF, AURA

说明: 你看过的绿闪能玩这种把戏吗？日落时分的绿闪是一种罕见的事件，也因此，许多太阳观察者都以曾亲眼目睹为荣。绿闪曾被认为只是一种迷思，然而现在的人们知道，当地球大气兼具棱镜及透镜的功能时，就会发生绿闪。不同高度的大气分层所产生的光折射也不同，因此，可让源自太阳顶部的光线发生分光，形成2个图像，并将之适当放大，让日盘即将消失前的最后一抹银白带着泛绿的色泽。不过，这幅图像所呈现的则是更不寻常的日落。在去年4月的某一天，从位于智利的高海拔托洛洛山美洲天文台，拍摄到太阳往具有多个不同热分层的大气后方沈降，形成太阳的多重蜃像。而在这次及这个位置，数个分层同时产生了绿闪。就在这个多重绿闪事件，为2位大吃一惊的天文摄影者记录之后的数秒钟，太阳就没入云层之下。

明日的图片: dolphin vs cloud