How many times have you taken a picture of the sun or moon with your smartphone and when you looked at the picture you saw things that you didn’t notice when you looked up at the sky?! It happens frequently and in most cases, it’s simply the bright light of a relatively small object that reflects inside the glass of your camera lens. It often appears as a dot, and many times it will have a partial circle or oval with a glow around the dot. It might also be tinted blue or purple or even green!
These are called lens artifacts or lens flares and they happen in all photography. It’s more noticeable when any part of your lens is flat- like the outside of a cameraphone lens, or the flat lens filter many photographers use on DSLRs and even film cameras.
Many people noticed it for the first time during the eclipse of 2017 http://www.businessinsider.com/solar-eclipse-photos-blue-crescents-lens-flare-2017-8 Others notice when they try to take a sunset picture http://aty.sdsu.edu/observing/artifacts.html
You can easily see how it happens by pointing your camera toward a small bright light at night. As you move your camera around, you’ll see the reflection moving around the image before you take it. This also happens in video cameras. The next time you watch a sporting event on TV and the camera points up toward the sky or even bright lights of a stadium at night, look, and you’ll see it!