NASA's APOD spotlights the race to catch the Moon's shadow

The September 5, 2026 Astronomy Picture of the Day, titled "Chasing the Moon's Shadow", turns the spotlight on eclipse chasers and the fleeting umbra that sweeps across Earth during a total solar eclipse.

NASA's Astronomy Picture of the Day for September 5, 2026 carries the title "Chasing the Moon's Shadow". As with every APOD entry, the image is accompanied by a short explanation written by a professional astronomer and is available through NASA's science portal as well as the long-running APOD archive.

The theme fits the season: only weeks earlier, on August 12, 2026, the Moon's umbra raced across the Arctic, Greenland, Iceland and northern Spain during a total solar eclipse. Photographers and scientists routinely position themselves - on the ground, at sea or aboard aircraft - along the narrow path of totality to capture the dark cone of shadow as it crosses the landscape at supersonic speed.

The Moon's shadow is a rare sight because the umbra is typically only a few hundred kilometres wide and lingers over any single spot for at most a few minutes. Views from high altitude or from orbit reveal it as a dark oval moving across clouds and terrain, which is why such images are prized both for their beauty and as records of the geometry of the Sun-Earth-Moon system.