Why your picture of the eclipse might have a little blue crescent hidden in it

Emily Cohn/Business Insider

On Monday, the entire US got to see a solar eclipse. 

During the event, many people turned their cameras to the sky to get a snapshot of the eclipse in all its glory. 

It was safe to take a picture through a smartphone, though the photos didn't get the NASA-level quality you'd see from an angle lens.

Instead, the photos tended to show the sun blown out in a blaze of light - not the crescent shape of a partial eclipse. But in some photos, a crescent did appear; it was just far from the actual sun and looked blue. You can see a clear example of this in the photo on the right, which was taken by Business Insider's Emily Cohn near New York's Flatiron building.

The effect is a "lens flare," which happens when a camera is exposed to a bright light. In response, the lens captures some of the light as a reflection. Lens flares generally show up as little dots or circles, but during an eclipse they appear as small crescents. 

Another crescent-shaped lens flare is visible in a photo tweeted by Senator John McCain, which his staff captured near the US Capitol.

The same effect happened when Business Insider's Rebecca Harrington snapped a picture of the sun through welding glass. This time, three crescent suns are visible because of lens flare.  

Rebecca Harrington/Business Insider

If you were hoping to capture what the eclipse looked like from your location, the crescent reflections that come out as lens flares are actually a pretty good representation. They are similar to the projections you might have seen through leaves, pinhole cameras, or even your fist. 

Rebecca Harrington/Business Insider