The largest and most powerful optical telescope in the continental United States has just taken its first look at the universe, demonstrating the feasibility of its novel design and ushering in a new era of cost-effective large telescopes.
The milestone event known as "first-light," was announced today by board members, engineers, and astronomers associated with the new William P. Hobby-Robert E. Eberly Telescope (HET) Project, a partnership involving The University of Texas at Austin, The Pennsylvania State University (Penn State), Stanford University, and the German universities Georg-August-Universität Göttingen and Ludwig-Maximilians-Universität München.
With its visitors' gallery, the HET will be the largest telescope in the world visible to the public. It will be commissioned in late 1997 at McDonald Observatory in the Davis mountains, a remote area of western Texas, recognized as having the darkest skies in North America.
The $13.5-million Hobby-Eberly Telescope is named for former Texas Lieutenant-Governor Bill Hobby and for Robert Eberly, a Penn State benefactor. "HET partner institutions now have access to one of the very largest telescopes in the world at a cost one-fifth of others in its class," says Frank Bash, Director of McDonald Observatory.
The HET's cost-saving design eliminates many of the expensive features that give a standard telescope its all-purpose flexibility. The telescope employs the largest primary mirror in the world, 11 meters (432 inches) in diameter. The mirror consists of 91 identical 1-meter hexagonal mirror segments that can be cost-effectively produced in quantity. Another cost-saving feature is that, in contrast to most telescopes, the HET tracks objects as they move across the night sky not by rotating the entire telescope but by moving just a few focusing instruments suspended above the primary mirror. This engineering concept reduces by more than 10 times the amount of telescope mass that must be moved under precise control. The telescope's schedule will be computer controlled to allow many different types of observations to be made in a single night. This design feature improves the overall efficiency of the telescope and allows the HET to seize opportunities to study short-lived astronomical events.
"We are very pleased that we have been able to stay within the established HET budget and have progressed from groundbreaking to first-light in less than three years," says Thomas A. Sebring, the HET Project Manager. "Already astronomers in Australia, South Africa, Chile, and Germany are discussing the possibility of building a telescope of the HET design in the southern hemisphere."
Astronomers are planning to use the Hobby-Eberly Telescope to search for planets around other stars, to study the origin of the elements in our own galaxy, to measure the properties of black holes, to probe for the existence of dark matter in and around galaxies, and to investigate the early history of galaxies and the universe. "I applaud the members of the project engineering team for the huge efforts and long hours they have invested to make first-light happen," says Dr. Lawrence W. Ramsey. Ramsey is the HET Project Scientist and, he and Daniel Weedman, both a Professors of Astronomy and Astrophysics at Penn State, are co-inventors of the HET concept.
On the evening of 10 December, the telescope provided seeing-limited images of three arc seconds and raw, unguided tracking accuracies of better than 0.1 arc sec/sec. This performance was established six hours after initial alignment of mirror segments, in winds gusting to 25 mph.
During the commissioning period, expected to last until August 1997, Sebring and Ramsey will lead a team of engineers and astronomers as they refine the telescope's engineering performance and bring it into full operation. "With first-light, the HET has just started the final stretch towards being able to do the scientific work it was designed for," Ramsey says. "We will now start to bring it up to its full power and it will be heavily engaged in science observations by the end of 1997."
Photographs are available on the Web sites or from the project office at 512/471-5323, fax 471-7199.
Contact: Thomas A. Sebring, Project Manager
Hobby-Eberly Telescope Project
512/471-5323, fax 512/471-7199
e-mail: sebring@astro.as.utexas.edu
Web sites: http://www.as.utexas.edu/mcdonald/het/het.html
http://www.as.utexas.edu/mcdonald/het/het-pictures.html
http://www.astro.psu.edu/het/