UA NEWS SERVICES May 13, 1998

UA ASTRONOMER OBSERVES HISTORIC EVENT IN BRAZIL

Web image

The image is also featured on the UA science Web page An astronomer from The University of Arizona in Tucson and four Brazilian amateur astronomers last month observed an event not witnessed from Earth in more than a thousand years, if ever.

Erich Karkoschka, a senior research associate with the UA Lunar and Planetary Laboratory, and his colleagues on April 23 photographed the moon as it simultaneously occulted Venus and Jupiter. They made the observation from Brazil's east coast 100 kilometers north of Recife, near the easternmost point of the American continent.

"This event was visible in the night sky of the southern Atlantic Ocean, including a few islands and a small part of Brazil," Karkoschka said. "At no other time during this millennium was such an event visible in the night sky anywhere on Earth."

The image shows the overexposed moon together with Venus and Jupiter at the top, next to the silhouette of a palm tree. Farther down are stars of the constellation Aquarius in the light of beginning dawn. On the very bottom is the reflection of the combined light of the moon, Venus and Jupiter in the waves of the ocean. The inset at lower left is a view with a telephoto lens taken at about the same time. The inset at lower right was taken one hour earlier through haze with a band of clouds below, soon after Venus and Jupiter emerged behind the limb of the moon. Venus, brighter than Jupiter, is to its lower left. The images were exposed on Kodak Elite 400 with 50mm and 400 mm lenses.

"The Brazilians found a good observing place," Karkoschka said. "At midnight, three hours before the event, they succeeded in convincing a local home owner that his platform overlooking the ocean would be the perfect place to set up four telescopes."

While this event was impressive when viewed by naked eye, the 4-inch telescopes revealed features not visible at other times, he added. "For example, as Venus started to go behind the lunar limb, its bright white cloud cover was in remarkable contrast to the dark yellow-brown lunar surface."

The weather was changing quickly. "Clouds were coming and going," Karkoschka said. "Sometimes it sprinkled while the view to the moon was clear."

During the last millennium, there was a double occultation of Venus and Jupiter by the moon on the morning of August 18, A.D. 567, visible from the northwest corner of the Indian Ocean. It occurred closer to the sun and could not be observed from Earth as well as this year's event, Karkoschka said.

"It is not known if anybody observed the A.D. 567 occultation. Given the rarity of such an event and the small zone of visibility, there may be no record that such an event has been observed before in the history of mankind," he said.

"When prehistoric people saw such a close gathering of the three brightest objects in the night sky, they must have been taken by awe. By comparison, the constellations believed to be the famous star of Bethlehem in connection with the birth of Jesus Christ were much less impressive."

"Only very few people saw this year's event since most people within the zone of visibility were asleep at that time," he said.


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