Subscribe to our free daily newsletters
. 24/7 Space News .

Subscribe to our free daily newsletters

Io Surface Captured in Full Motion

Surface details captured with Keck adaptive optics in the K-band (upper left) show a comparable level of detail to visible light picture taken with the NASA Galileo orbiter (upper right). The L-band image (lower left) is dominated by active volcanic hot spot emissions, such as Loki, located near the center of the disk. These spots can now be monitored from the ground. An image of Io without adaptive optics (lower right) shows what the keck telescope would see without adaptive optics. Note that no hot spots are detected in this image. More Images and Animations
Albuquerque -June 3, 2002
The highest resolution infrared global images ever taken of Jupiter's volcanic moon, Io, are now available from the W.M. Keck Observatory and UC Berkeley in a unique animated movie and 3D Java applet. The images provide a complete survey of Io's surface during one full rotation and demonstrate the power of adaptive optics, enabling astronomers to study phenomena from the Earth that previously could be studied only from space.

"Adaptive optics technology is now able to produce eightfold improvements in image quality beyond what has previously been possible", said Dr. Frederic H. Chaffee, director of the W. M. Keck Observatory. "The Io images released today show features on its surface as small as 60 to 120 miles across. This is equivalent to being able to distinguish the two headlights of a single car in St. Louis while looking at them from Los Angeles, 1800 miles away."

The Keck II 10-meter mirror telescope, with its adaptive optics system, provides the highest resolution pictures ever taken from an Earth-based telescope. The Keck images released today show a similar level of detail to data taken by the NASA's Galileo orbiter, a spacecraft that came within 400,000 miles of Io's surface. By contrast, the Keck telescopes on Earth are more than 390 million miles away (1000 times farther) from Io.

"Observations such as these are the only method by which we can obtain complete spatial coverage of Io volcanic activity and at resolutions better than what we find with the global Galileo data for this wavelength range", said Dr. David Le Mignant, W.M. Keck Observatory.

The Io movie was produced from 14 pictures taken with the Keck infrared camera (NIRC2) placed behind the adaptive optics system.

This camera is capable of producing images with a Strehl ratio of up to 85 percent. Strehl is a measure of the corrected image and a Strehl ratio of 100 percent equals a fully corrected, perfect image.

The quality of these images is so high, it's as if the Keck telescope were taking pictures from space.

The images of Io were taken at a wavelength of 3.5 microns (L-band) and were spaced approximately 25 degrees apart in Ionian longitude such that the entire surface of Io was recorded during a six-night period in December 2001.

The contrast and resolution of the images were then increased by using a numerical process named Myopic Iterative Step Preserving Restoration Algorithm (MISTRAL), a deconvolution, or image enhancement, method developed for planetary observations by the Office National d'Etudes et de Recherche Aerospatiales (ONERA). Then, the images were converted to an animation to show one full rotation of Io as it orbits Jupiter.

Finally, the W.M. Keck Observatory created a Java applet to add interactive control and synchronous comparisons to pictures taken at visible wavelengths with the Galileo orbiter.

Infrared wavelengths are important for understanding thermal emissions associated with Ionian volcanic features. The infrared wavelength of 2.2 microns (K-band) gives astronomers information about reflected sunlight modulated by various surface features.

Infrared wavelengths at 3.5 microns (L band) give astronomers information about thermal volcanic activity with the highest level of contrast between hot magma and reflected sunlight.

"These new observations give important clues about the temperature and composition of Io's volcanic structures such as lava lakes, fire fountains, calderas and lava tubes. With the Galileo mission ending, adaptive optics systems will be the only tools available to study this exotic extra-terrestrial volcanism," said Dr. Franck Marchis of UC Berkeley.

The project to image the surface of Io and demonstrate the imaging performance of the Keck adaptive optics with NIRC2 is being led jointly by Dr. David Le Mignant (W.M. Keck Observatory) and Dr. Franck Marchis (UC Berkeley). Team members include S. Kwok, P. Amico, R. Campbell, F. Chaffee, A. Conrad, A. Contos, B. Goodrich, G. Hill, D. Sprayberry, P. Stomski, P. Wizinowich (W.M. Keck Observatory) and Dr. I. de Pater (UC Berkeley).

Related Links
Keck Observatory
Search SpaceDaily
Subscribe To SpaceDaily Express

Io's Volcanos Vent Far From Jupiter
College Park - Mar 4, 2002
A huge cloud of gas, spewed from volcanos on one of Jupiter's moons, extends into space to a distance that is almost equal to that of the earth from the sun, says a new report published in the journal Nature.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.