NASA's Astronomy Picture of the Day for August 2, 2026, featured a circumhorizontal arc photographed in 2021 near North Fork Mountain in West Virginia, credited to Christa Harbig. The image's accompanying explanation describes the phenomenon, informally called a fire rainbow for its flame-like appearance, as an arc that appears parallel to the horizon.

The explanation states that ice crystals in a distant cirrus cloud act like floating prisms. For a circumhorizontal arc to be visible, the Sun must be at least 58 degrees high, with cirrus clouds present below—in this case cirrus fibratus. The flat, hexagonal ice crystals making up the cloud must be aligned horizontally to refract sunlight in a collectively similar manner, which the explanation notes makes such arcs somewhat unusual to see.

The page was authored and edited by Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti and Keighley Rockcliffe, and presented as a service of NASA's Astrophysics Science Division at Goddard Space Flight Center, NASA Science Activation and Michigan Technological University. It also listed the previous day's image, of a Buck Moon and the Belt of Venus, and the following day's, of a meteor photobombing the Lacerta Nebula.