Historic Venus Transit Captured by NOAA's GOES-15

June 7, 2012

On June 5, the planet Venus made its final 21st Century trek across the face of the Sun as seen from Earth until the year 2117. GOES-15 (Geostationary Operational Environmental Satellite-15) captured the entire event from its position 22,300 miles above the Earth. NOAA and NASA satellites recorded and archived the historical images which will not be seen again for more than a century.

"This is a once in a lifetime event, it's very exciting" says Natalia Donoho, Services Coordinator, NOAA Satellite and Information Service, Satellite Products and Services Division.

The Venus transit took almost seven hours to complete (as viewed from Earth). This transit was observed by the solar imager on the GOES-15 spacecraft. Images from the Solar X-ray Imager, or SXI instrument, are normally used to detect solar flares.

A transit of this type has helped astronomers for more than a century chart the distance of the Earth and Sun (the Astronomical Unit). This measurement gives scientists a basis in determining the size of the solar system.

The Venus transit can only occur in December or June during the time when the orbit of Venus passes the Sun. According to the National Aeronautics and Space Administration, transits show a clear pattern of recurrence at intervals. The transits patterns occur eight years apart separated by 121.5 years and 105.5 years. The next pair of Venus transits are expected to take place on December 11, 2117, and December 18, 2125.

The GOES-15, the newest geostationary satellite, took the place of GOES-11 and is now NOA's GOES West spacecraft. The spacecraft has a fixed orbit over the Pacific Ocean, midway between Hawaii and the West Coast, and provides more data with better resolution and image stability than GOES-11. GOES-15 joins NOAA's other operational geostationary satellite, GOES-13, which serves as the GOES East spacecraft.

The GOES are not only used for weather applications, but also track space weather, oceanographic changes, forest fires and other hazards and provide scientific data collection and information for search and rescue operations. The satellites provide constant coverage of the western hemisphere by taking photographic images every 15 minutes.

View the Venus transit animation on the NOAA Visualization Lab site at: http://www.nnvl.noaa.gov/MediaDetail2.php?MediaID=1087&MediaTypeID=3&ResourceID=104631.

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