彩虹树

2023年3月13日

Rainbow Tree
Image Credit & Copyright: Eric Houck

Explanation: What lies at the end of a rainbow? Something different for everyone. For the photographer taking this picture, for example, one end of the rainbow ended at a tree. Others nearby, though, would likely see the rainbow end somewhere else. The reason is because a rainbow’s position depends on the observer. The center of a rainbow always appears in the direction opposite the Sun, but that direction lines up differently on the horizon from different locations. This rainbow’s arc indicates that its center is about 40 degrees to the left and slightly below the horizon, while the Sun is well behind the camera and just above the horizon. Reflections and refractions of sunlight from raindrops in a distant storm in the direction of the rainbow are what causes the colorful bands of light. This single exposure image was captured in early January near Knight’s Ferry, California, USA.

Tomorrow’s picture: Soul of the night

彩虹树
图像提供与版权: Eric Houck

说明: 彩虹的尽头有什么？所见因人而异。例如，对于拍下此照片的摄影者来说，彩虹的尽头有绿树。不过，附近的其他人看到的彩虹可能止于其他地物。这是因为彩虹出现的位置取决于观察者。不过，彩虹的中心总是与太阳反向，但对不同的观察者，该方向可在地平线不同的位置。这道彩虹的光弧显示，它的中心位于往左约40度、略低于地平线的位置，而太阳则紧贴在相机后面的地平线上方。从彩虹后方远处的雷暴云降下的雨滴，反射和折射阳光造就了这道色彩缤纷的光带。这张单曝光图像，是在今年1月初摄于美国加州的奈特渡口附近。

明日的图片: Soul of the night