Washington:
Citizens of Earth, get ready for your close-up from thousands of miles away! NASA's Cassini spacecraft will be taking the first-ever natural-colour image of the Earth as seen from the Saturn system, from 1.44 billion kilometres away on July 19.
The US space agency is inviting the public to help acknowledge the historic interplanetary portrait as it is being taken.
Earth will appear as a small, pale blue dot between the rings of Saturn in the image, which will be part of a mosaic, or multi-image portrait, of the Saturn system Cassini is composing, NASA said.
"While Earth will be only about a pixel in size from Cassini's vantage point 1.44 billion kilometres away, the team is looking forward to giving the world a chance to see what their home looks like from Saturn," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.
"We hope you'll join us in waving at Saturn from Earth, so we can commemorate this special opportunity," Spilker.
Cassini will start obtaining the Earth part of the mosaic at 5:27 pm EDT and end about 15 minutes later, all while Saturn is eclipsing the Sun from Cassini's point of view.
The spacecraft's unique vantage point in Saturn's shadow will provide a special scientific opportunity to look at the planet's rings. At the time of the photo, North America and part of the Atlantic Ocean will be in sunlight.
Unlike two previous Cassini eclipse mosaics of the Saturn system in 2006, which captured Earth, and another in 2012, the July 19 image will be the first to capture the Saturn system with Earth in natural colour, as human eyes would see it.
It also will be the first to capture Earth and its moon with Cassini's highest-resolution camera. The probe's position will allow it to turn its cameras in the direction of the Sun, where Earth will be, without damaging the spacecraft's sensitive detectors.
Carolyn Porco, Cassini imaging team lead at the Space Science Institute in Boulder and her imaging team associates examined Cassini's planned flight path for the remainder of its Saturn mission in search of a time when Earth would not be obstructed by Saturn or its rings.
Working with other Cassini team members, they found the July 19 opportunity would permit the spacecraft to spend time in Saturn's shadow to duplicate the views from earlier in the mission to collect both visible and infrared imagery of the planet and its ring system.
This latest image will continue a NASA legacy of space-based images of our fragile home, including the 1968 "Earthrise" image taken by the Apollo 8 Moon mission from about 380,000 kilometres away and the 1990 "Pale Blue Dot" image taken by Voyager 1 from about 6 billion kilometres away.
