This was a full rainbow but by the time I got the camera and ran past the cable and electric wires, much of the arc had faded. Still I was happy to capture and share a partial arc.
Rainbows are actually full circles, but they appear as arcs because the horizon blocks the lower part of the circle.

Nikon P1000

crop, convert raw to jpg, color adjust in Photoshop, Franzis 4Pro