Moonbow

This image is a bit different from my usual astrophotography work.

The bright arc across the frame is not an aurora, a nebula, or a processing effect. It was created by the light of the full Moon, sitting just outside the field of view, being refracted through the telescope optics. The result is a large rainbow-like curve projected against the background stars.

Technically, this is an optical artifact: exactly the kind of thing we usually try to avoid in astrophotography. But in this case, I liked the result too much to discard it. The full Moon turned the telescope into an unexpected prism, creating a “moonbow” across the sky.