CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Blue Orb On The Horizon

Blue Orb On The Horizon
PIA 17178

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  This view from NASA's Cassini spacecraft features a blue planet, but unlike the view from July 19, 2013 (PIA17172) that featured our home planet, this blue orb is Uranus, imaged by Cassini for the first time.

Uranus is a pale blue in this natural color image because its visible atmosphere contains methane gas and few aerosols or clouds. Methane on Uranus - and its sapphire-colored sibling, Neptune - absorbs red wavelengths of incoming sunlight, but allows blue wavelengths to escape back into space, resulting in the predominantly bluish color seen here. Cassini imaging scientists combined red, green and blue spectral filter images to create a final image that represents what human eyes might see from the vantage point of the spacecraft.

Uranus has been brightened by a factor of 4.5 to make it more easily visible. The outer portion of Saturn's A ring, seen at bottom right, has been brightened by a factor of two. The bright ring cutting across the image center is Saturn's narrow F ring.

Uranus was approximately 28.6 astronomical units from Cassini and Saturn when this view was obtained. An astronomical unit is the average distance from Earth to the sun, equal to 93,000,000 miles (150,000,000 kilometers).

This view was acquired by the Cassini narrow-angle camera at a distance of approximately 614,300 miles (988,600 kilometers) from Saturn on April 11, 2014. Image scale at Uranus is approximately 16,000 miles (25,700 kilometers) per pixel. Image scale at Saturn's rings is approximately 4 miles (6 kilometers) per pixel. In the image, the disk of Uranus is just barely resolved. The solar phase angle at Uranus, seen from Cassini, is 11.9 degrees.

The Cassini Solstice Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini Solstice Mission visit, and

Credit: NASA/JPL-Caltech/SSI
Released: May 1, 2014 (PIA 17178)
Image/Caption Information

Alliance Member Comments
Ashvin (Jul 7, 2015 at 1:26 AM):
Hi, I just want to say that this is a simply spectacular image of Uranus from such an extreme distance. I would like to know if Dr. Porco and the rest of the Imaging Team plan to have Cassini take a similar picture of Neptune, anytime between now and the end of the mission? I know that a lot of the spacecraft's resources are currently allocated to things like moon flybys and studies of Saturn itself, but I was just wondering if there would be an opportunity for Cassini to squeeze in a picture of Neptune, just like with this image of Uranus?
NeKto (May 14, 2014 at 11:33 AM):
Bigger blue marble