Anticrepuscular Rays Near Cordoba

January 19, 2006


Provided and copyright by: John Coppens, Catholic University at Córdoba
Summary authors & editors: John Coppens

Just after classes this past November at the Catholic University in Cordoba, Argentina, students asked me to explain the strange sky shown above. The breathtaking rays were coming from the east, while the Sun was setting in the west (see inset). However, the actual form of these rays was determined by clouds in the vicinity of the Sun. Hence, these are anticrepuscular rays. When conditions are just right, twilight rays from the setting Sun stretch across the sky and converge on the eastern horizon. The fact that the rays appear to converge toward the horizon is due to the observers perspective -- they're actually parallel to one another. At left is the Electronics Engineering building, and at right is the Systems Engineering building on the campus of the Catholic University.

Related Links: