APOD: 2026 August 28 – The Sky Turns Above Paranal

On August 28, 2026, the Astronomy Picture of the Day (APOD) featured a captivating image capturing the sky's rotation above Paranal Observatory in Chile. The observatory, situated at a latitude of 25 degrees south, experiences Earth's rotation moving its surface at speeds exceeding 1,500 kilometers per hour. Despite the rapid motion being faster than the speed of sound at sea level, it remains unnoticeable to the human eye.

However, the motion can be observed through star trail photography, which involves photographing star trails over an extended period. This particular image was created by combining 300 consecutive 25-second exposures using a camera fixed to a tripod. The resulting star trail arcs are concentric and centered around the south celestial pole, which represents the southern extension of Earth's axis of rotation into space.

One of the observatory's operating 1.8-meter auxiliary telescopes, designated AT 3, is visible beneath the south celestial pole, faintly illuminated in the foreground of the image. APOD's official NASA website, previously hosted at apod.nasa.gov, has since been moved to science.nasa.gov/apod. The picture was credited to Osvaldo Castillo and authored by a team of editors, including Jerry Bonnell, Cecilia Chirenti, Robert Nemiroff, and Keighley Rockcliffe.

This APOD service is operated by the Astrophysics Science Division at NASA/GSFC, NASA Science Activation, and Michigan Tech. University.