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Cassini is Going to Compose a Special Portrait of Saturn … and You!
By Linda Spilker
June 18, 2013
June 18, 2013
One of the most exciting Cassini events in 2013 will be the unusual
opportunity on July 19 to image the whole Saturn system as it is backlit
by the sun. With Saturn covering the harsh light of the sun, we will
be gathering unique ring science and also catching a glimpse of our very
own home planet.
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This
simulated view from NASA's Cassini spacecraft shows the expected
positions of Saturn and Earth on July 19, 2013, around the time Cassini
will take Earth's picture. Cassini will be about 898 million miles (1.44
billion kilometers) away from Earth at the time. That distance is
nearly 10 times the distance from the sun to Earth. Image credit:
NASA/JPL-Caltech
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The main science goal for the mosaic we are making of the Saturn
system is to look at the more diffuse rings that encircle Saturn and
check for change over time. A previous mosaic of the Saturn system
Cassini made in 2006 revealed that the dusty E ring, which is fed by the
water-ice plume of the moon Enceladus, had unexpectedly large
variations in brightness and color around its orbit. We'll want to see
how that looks seven Earth years and a Saturnian season later, giving us
clues to the forces at work in the Saturn system. We'll do this
analysis by collecting data from our visual and infrared mapping
spectrometer, composite infrared mapping spectrometer and ultraviolet
imaging spectrograph in addition to the imaging cameras.
But one of the best parts of the mosaic we're making on July 19 is
that we'll be able to take a picture of Earth – and all of you -- from
about 898 million miles (1.44 billion kilometers) away. The Earth will
appear to be just a pixel, but you can see in this simulated close-up
what parts of it will be illuminated.
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North
America and part of the Atlantic Ocean are expected to be illuminated
when NASA's Cassini spacecraft takes a snapshot of Earth on July 19,
2013. This view is a close-up simulation. Image credit:
NASA/JPL-Caltech
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Opportunities to image Earth from the outer solar system are few and
far between and special care must be taken so we don't blind our cameras
by looking in the direction of the sun, where Earth is. There have been
only two images of Earth from the outer solar system in all the time
humankind has been venturing out into space. The first and most distant
was one was taken 23 years ago by NASA's Voyager 1 spacecraft from 4
billion miles (6 billion kilometers away), showing
The other opportunity was
We think Cassini's July image is a special opportunity for Earthlings
to wave at our photographer in the Saturn system and learn more about
my favorite planet, its rings and moons. We hope you'll go outside, look
in the direction of Saturn and send us pictures of yourselves waving.
You can share your pictures by joining our Flickr group Wave at Saturn, adding them to our Wave at Saturn Facebook event page or tagging pictures on Twitter #waveatsaturn. We hope to make a special collage of all these images if we get enough of them.
The Cassini portrait session of Earth will last about 15 minutes from 2:27 to 2:42 p.m. PDT (21:27 to 21:42 UTC).
Another blog post by Jane Houston Jones, provides more information about where to look in the sky.
Linda Spilker is the Cassini project scientist, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
Cassini Probe to Take Photo of Earth From Deep Space
WASHINGTON - NASA's Cassini spacecraft, now exploring Saturn, will take
a picture of our home planet from a distance of hundreds of millions of
miles on July 19. NASA 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.
"While Earth will be only about a pixel in size from Cassini's vantage point 898 million (1.44 billion kilometers) 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, Calif. "We hope you'll join us in waving at Saturn from Earth, so we can commemorate this special opportunity."
Cassini will start obtaining the Earth part of the mosaic at 5:27 p.m. EDT (2:27 p.m. PDT or 21:27 UTC) 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 color, 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.
"Ever since we caught sight of the Earth among the rings of Saturn in September 2006 in a mosaic that has become one of Cassini's most beloved images, I have wanted to do it all over again, only better," said Carolyn Porco, Cassini imaging team lead at the Space Science Institute in Boulder, Colo. "This time, I wanted to turn the entire event into an opportunity for everyone around the globe to savor the uniqueness of our planet and the preciousness of the life on it."
Porco 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.
"Looking back towards the sun through the rings highlights the tiniest of ring particles, whose width is comparable to the thickness of hair and which are difficult to see from ground-based telescopes," said Matt Hedman, a Cassini science team member based at Cornell University in Ithaca, N.Y., and a member of the rings working group. "We're particularly interested in seeing the structures within Saturn's dusty E ring, which is sculpted by the activity of the geysers on the moon Enceladus, Saturn's magnetic field and even solar radiation pressure."
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 240,000 miles (380,000 kilometers) away and the 1990 "Pale Blue Dot" image taken by Voyager 1 from about 4 billion miles (6 billion kilometers) away.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington, and designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team consists of scientists from the United States, the United Kingdom, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
To learn more about the public outreach activities associated with the taking of the image, visit:
For more information about Cassini, visit
NASA
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
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