Dewbow

A dewbow is an optical effect, similar to a rainbow, where dewdrops instead of rain droplets reflect and disperse sunlight.

It forms most easily on surfaces that are isolated from conducted heat from deep ground, such as grass, leaves, and spider webs.

[3] A rainbow is perceived as a circle in the sky; and its contributing light rays form a cone.

If the ground is flat and horizontal, and the sun is low in the sky, the dew bow is a hyperbola.

Theoretically, when the sun is high, the intersection might be another conic section, like a parabola or an ellipse.