AAO image reference MISC 7. « Previous || Next »
Image and text © 1991-2002, Anglo-Australian Observatory, Photograph by David Malin.
On June 15, 1991, after weeks of rumbling and venting steam and poisonous gas, Mt Pinatubo exploded on the island of Luzon, in the Phillipines. This was the largest volcanic eruption for nearly a century. The eruption killed over 700 people and ejected several cubic kilometers of dust and gas over 35km high into the stratosphere.
The effects were felt around the world and included a temporary global cooling and a thinning of the ozone layer as well as other changes in the global weather pattern. However, the most obvious effect for many people was a milkiness in the daytime sky due to scattering by high altitude aerosols, and corresponding anomalous sunsets and twilights that were noticable for years.
This picture was made in early 1992, two hours after sunset, when it is usually completely dark. However, high altitude dust in the stratosphere reflected sunset colours strongly enough for them to be seen (in the sky, at right) and to be reflected again, by the AAT dome. The red reflection was captured in this six-hour exposure. Here the camera is pointing due south, directly at the south celestial pole. However, the position of the pole is hidden by the AAT dome. The appearance of the twilight sky immediately after sunset is seen here.
Related image
MISC 17. Pinatubo dust colours the twilight