Scientists pinpoint centre of Saturn to within just 2 miles
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Saturn and its moons may be nearly a billion miles away, but scientists now say they can pinpoint their location to within just two miles (4 km).
The discovery was made using ten antennae spread over an area from Hawaii to the Virgin Islands.
The calculation improves astronomers' knowledge of Saturn's orbit and could allow Nasa to better navigate its probes through space.
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Saturn and its moons may be nearly a billion miles away, but scientists now say they can pinpoint their location to within just two miles (4 km) after using data from the Very Long Baseline Array and the Cassini probe
Known as the Very Long Baseline Array (VLBA), the antenna assembly used signals sent by the Cassini probe to exactly monitor the position of the gas giant.
They combined this data with information about Cassini's orbit from Nasa's Deep Space Network.
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The combined observations allowed the scientists to make the most accurate determinations yet of the position of the centre of mass, or barycentre, of Saturn and its numerous moons.
Nasa claims the measurement is some 50 times more precise than those provided by ground-based optical telescopes.
The Very Long Baseline Array (VLBA) antenna assembly used signals sent by the Cassini probe to exactly monitor the position of the gas giant. Pictured are the location of the ten sites
Nasa claims the measurement of Saturn and its moons using its new method is now some 50 times more precise than those provided by ground-based optical telescopes.
'This work is a great step toward tying together our understanding of the orbits of the outer planets of our solar system and those of the inner planets,' said Dayton Jones of JPL, who led the study.
The improved accuracy will help enhance precise navigation of interplanetary spacecraft and help refine measurements of the masses of solar system objects.
It will also improve predictions of when Saturn or its rings will pass in front of background stars -- events that provide a variety of research opportunities for astronomers.
Previously, the navigators performed their own estimates of the positions of Saturn and its satellites using data gleaned by tracking Cassini's radio signal during its communications with Earth.
The new calculations, enhanced by VLBA data, are about 20 times more accurate.
Professor Jones and colleagues plan to continue the joint observations with Cassini and the VLBA through the end of Cassini's mission in late 2017.
The team will also use similar techniques to observe the motion of Nasa's Juno spacecraft when it reaches Jupiter in mid-2016.
The findings were reported at a meeting of the American Astronomical Society in Seattle.
The Very Long Baseline Array (VLBA) is a system of ten radio-telescope antennas,each with a dish 82ft (25 metres) in diameter and weighing 240 tonnes. Pictured is the VLBA site in Owens Valley, California
The team at Nasa combined the data with information about Cassini's orbit (artist's impression pictured)
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