Dew bow

The rainbow is caused by the refraction and reflection of sunlight in raindrops. However, the appearance of the "rainbow" is not limited to rain and can also be observed in other droplet accumulations, such as spray from ships (sea spray), waterfalls, or dew drops on a meadow. Dew forms mainly in spring and autumn, when clear nights cause the ground to cool significantly, leading to the condensation of water vapor. The dew bow is essentially the lower continuation of the rainbow, projected onto a horizontal surface. One would have to be able to observe a semicircle whose apex lies at the end of the observer's shadow and opens outward. In practice, often only a colorful glow is noticeable at the sides of the "rainbow." Backscattering and the weak contrast to the green of the grass are likely responsible for this. The dew bow is more noticeable when the dew drops are on spider webs, which can be widespread over the meadow, especially at forest edges, primarily in autumn. Unfortunately, a dew bow is not very frequently observed. If the sun is very low, the length of the shadow makes it difficult to see the dew bow. As the sun rises, the dew evaporates quickly, and when the shadow's end is finally in sight, usually not enough dew remains to produce a "rainbow." Therefore, forest clearings or meadows that remain in shadow for a long time in the morning are best suited for observation.