Pale Blue Dot

NASA just released a panoramic image of Saturn and some of its closest moons, but it also includes the tiny, blue dot we call home – planet Earth, some 900 million miles away.  Taken by the Cassini probe now orbiting Saturn, the image also captures our companion worlds Venus and Mars.  The panorama was pieced together from natural-color photographs taken in July.

Each pixel in the photograph represents about 45 miles. Seven out of Saturn’s 53 known moons are visible in their planet’s seven rings. There’s Prometheus, Pandora, Janus and Epimetheus near Saturn’s slim F ring. There’s Enceladus in the bright blue E ring. There’s Tethys, a yellow bulb, and Mimas, just a crescent, wedged between rings.

Cassini at Saturn 1

Venus is located to Saturn’s upper left, which is seen as a bright, white spot.  Mars, a pale red dot, is above and to the left of Venus. There are 809 stars captured by Cassini’s lens in this image.  And we Earthlings are on the blue dot at Saturn’s lower right.

This cosmic portrait had been planned for months and on July 19, NASA announced that all the conditions were right for such a picture, including that on this date, Saturn completely eclipsed the sun, allowing Cassini’s sensors to image this portrait.  The cosmic photo is a composite of 141 images taken over four hours, selected out of 343 images total. The photograph was then digitally enhanced to pull from the blackness Venus, Mars, Earth, Saturn’s moons, and all the stars in the frame. Most of the objects in the photograph, including Earth, were brightened by 8 times relative to Saturn; some of the stars were brightened by as much as 16 times.

This was also the first time that humans were told in advance that Earth was being put before a camera. So, in what was called NASA’s “Wave at Saturn” campaign, the Cassini’s Imaging team asked us all to turn out for the July 19 picture day to wave and smile for the camera in the cosmos.

Cassini at Saturn 2

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NEW COMPLETE VIEW FROM BEYOND SATURN

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“On July 19, 2013, in an event celebrated the world over, NASA’s Cassini spacecraft slipped into Saturn’s shadow and turned to image the planet, seven of its moons, its inner rings — and, in the background, our home planet, Earth.”(NASA)

Remember when we wrote about the Casini Spacecraft photographing the Earth from the other side of Saturn?   Well, now all the data and pixels have been put together with a lot of hard work from the project scientists and the amazing result is here:

http://photojournal.jpl.nasa.gov/figures/PIA17172_fig1.jpg

Go look at the amazing image from across the solar system. You will be amazed…. Zoom in and look at the planets and other objects in the background.

Earth’s Group Photo

Staff at JPL celebrate Earth’s snapshot.

Last week, people all across the world waved at the skies in a group celebration of Earth’s portrait shot from 898,000,000 miles away. The Cassini spacecraft has been orbiting Saturn for nearly a decade, and in fact most of the dazzling images you’ve seen of Saturn, its rings, and its moons were captured by Cassini. On Friday, July 19, 2013 Cassini’s cameras captured images of Earth, the Moon, and Saturn in the same image frame. This wasn’t the first time Earth’s picture was taken from the outer Solar System, but this time the event was made known to the public in advance of its happening. “Wave at Saturn” images flooded social media sites as waving people took pictures with hula hoops to show their excitement and support.

Artist’s conception of Cassini orbiting Saturn.

Today we saw the first images released of Saturn and Earth. It has taken several days for the images to be ready. Why is this?

Have you ever tried to take a picture in the dark? It’s difficult… You need to keep your camera still, and leave your shutter open for a long time to capture more light. The same idea applies here. Earth was 898 million miles away from Cassini when these pictures were taken, showing up as only a faint blue dot. To add to the challenge, bright and shiny Saturn sits in the foreground of the image. On top of this, Cassini is in motion as it orbits Saturn.  Imagine trying to take a picture of a car with its headlights on and a tiny firefly sitting in a tree behind it, while riding a bicycle past the scene….

Cassini accomplishes this by taking hundreds of images. These images were sent back to humans on Earth for processing. For the past several days, scientists at NASA have been combining these images together with special computer software. To put it simply, the images are layered on top of each other and combined to form a single image.

The finished product of Cassini’s Earth, Moon, and Saturn portrait is not yet complete. The image released today is one of 33 “tiles” of the final mosaic that will show the entire planet Saturn, its rings, and Earth. Creating this picture takes a lot of work. Stay tuned as more of the puzzle is pieced together…

The first image released by NASA of Earth, Moon, and Saturn’s group photo. Earth is marked by an arrow. The moon is barely visible as a faint smudge to the lower right. This image alone was created by combining over 200 individual images captured by Cassini.