A bright aurora borealis arcs through the starry sky of a Fairbanks winter night, its green hues visible even beside the moon's brilliant glow.
https://photos.lwpetersen.com/Galleries/Alaska-Photos/Aurora-Borealis/
@leepetersen
Awesome photo! Do you have an idea what caused those two large streaks through the moon?
@cweickhmann Just lens flare
@leepetersen
Intriguing. Afaik the term lens flare refers mostly to internal reflections within the optical column of the lens. It looks more like diffraction to me. But if you have such streaks, it's often perturbations like the shape of the diaphragm opening (often the six or eight streaks around light sources originate here).
Anyway: doesn't change the photo. 😉👍
@cweickhmann Diffraction causes very different patterns to emerge, typically a "washboard" effect or a "rainbow" effect. You are correct that internal reflection is one source of lens flare. That is exactly what is happening with the glint, or specular reflection (the streaks radiating from the moon); they occur because of reflection of the light source between the surfaces in the lens elements. The greenish blob is a lens flare effect called ghosting.
@leepetersen
Thanks! That's exactly the kind of explanation I was looking for. 👍
