The adaptive optics of the Keck Telescope in Hawaii can produce some stunning image enhancements. In 2004 teams from Berkeley/SSI and Wisconsin used the adaptive optics system to make dramatic new discoveries about the rings and atmosphere of Uranus. The Keck Observatory houses the world’s largest optical and infrared telescopes. The Keck I telescope went online in May 1993; Keck II started observing in October 1996. The Keck observatory has never really received the attention that hubbble gained for itself, despite its spectacular successes.

The image above illustrates the contrast between adaptive and unprocessed optics. Dr. Heidi Hammel and Dr. Imke de Pater

…took images of Uranus and its rings with the second-generation Near Infrared Camera (NIRC2) behind the AO system on the Keck II telescope, first with the AO system off, and then with the AO system on. In this figure, the ring system is more readily visible through the 2.2-micron filter because methane absorption at this wavelength renders the planet extremely dark except for a few high altitude clouds. In contrast, the 1.6-micron image shows deeper atmospheric cloud structure, including many discrete features peppering the planet’s northern hemisphere. At 1.6 microns, the rings are just barely visible as a faint streak across the planet’s northern hemisphere. [Keck Observatory]

Later the same year a team from University of Wisconsin-Madison also used the Keck II AO system, this time to investigate cloud structures:

These observations by the team at University of Wisconsin-Madison

…were formed into a composite image in which the highest clouds appear white, the middle level clouds appear bright green, and the lower clouds appear darker blue. The color balance used to reveal the cloud structure in these infrared exposures, which are not normally visible to human eyes, makes the ring system appear red in these images and is an artifact of the process. The higher clouds are most abundant in the planet’s northern hemisphere. [Keck Observatory]

Keck further added to our knowledge of Uranus in 2005 when De Pater and Hammel of the Space Institute in Boulder, Co. and Seran Gibbard of Lawrence Livermore National Laboratory, announced their observations of the new innermost ring [Keck Press Release]. The announcement was in an IAU circular, issued Dec. 22, the same issue carrying reports of the initial discovery of Uranus’ two new rings (subsequently published in Science)by Mark R. Showalter of the SETI Institute and Jack J. Lissauer of the NASA Ames Research Center, both located in Mountain View, Calif..

Needless to say, many more discoveries have followed

1. Showalter, M.R., Lissauer, J.L. (2006) “The Second Ring-Moon System of Uranus: Discovery and Dynamics,” Science 311(5763) pp973-977 [Online] Internet: http://www.sciencemag.org/cgi/content/abstract/311/5763/973 (accessed April 8, 2007).

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