It's been ten years since I took a single photo of what I call the Ring with a simple point-and-shoot digital camera. I blogged about it here, just before one of my appearances on Coast to Coast AM with Ian Punnett. The producer had to talk me into it because I'm not in the UFO club. But I was willing to hear facts, or grounded conjectures, that people had to pass along. And still am!
I was taking a photo of the contrail and didn't notice the Ring until months later, when flipping through the photos. Here's a wider view, then a cropped shot, enhanced with some contrast:
The post brought in a wide range of comments after the broadcast, with the skeptics weighing in first, saying that it was a lens flare, or a problem with the camera's JPEG processing, or a reflection onto a high, thin cloud layer.
The anvil chorus was followed by several commenters who said they'd seen similar things, some calling it a ring of plasma. The blue arc, just below the Ring, looks like it could be a shock wave from something climbing at supersonic speed. But no object is visible.
Ten years on, I haven't heard a credible conventional explanation. The least likely is lens flare, because I hadn't been pointing the camera anywhere near the direction of the Sun, given that I was aiming north and at this time of day, in Minnesota in May, the Sun was at least thirty degrees away.
While bright out-of-frame lights can cause a lens effect, typically it throws a haze over the image rather than creating a mysterious, single object.
JPEG can cause compression artifacts but I never saw any other odd object from this camera, and I'd run thousands of photos through it.