Observatories and Earthstations
Certain places on the earth have a special, unearthly function: these places are built to escape terrestrial limitations, to gaze upward and outward, to either interact with space probes and satellites, or to search for meaning beyond this world. In the interest of improving our understanding of the earth/sky interface, the Center has established a special focus area relating to observatories and earthstations. Here are two reports on compelling and superlative places within this constellation of remarkable constructions.
Arecibo, Puerto Rico: A Giant Ear Built Onto the Earth
LOCATED IN THE JUNGLE OF northern Puerto Rico, the famous Arecibo Radio Telescope is the largest single dish on earth. The observatory consists of an immovable 1000 foot wide, 18 acre parabolic bowl built in a natural depression, and pointing at the zenith, forming a radiowave collection dish - an "ear" that constantly listens to whatever might be out there.
Although it is most well known for its central role in the Search for Extraterrestrial Intelligence (SETI) project, its conception was military, and aspects of its original use remain mysterious. The telescope project was funded in 1960 by the Advanced Research Project Agency (ARPA), and was built in 1963 by Cornell University, under contract with the Air Force's Cambridge Research Laboratory, following the initiative of Cornell professor William Gordon from the Department of Electrical Engineering. The Air Force intended to use it for a variety of defense-related purposes, including scanning of the Earth's ionosphere to detect rocket launches.
By 1970, its military usefulness apparently waning, ARPA was ready to pull the plug on the facility. Some astronomers recognized that the telescope could be reengineered to become a very significant instrument for the then relatively new fields of radio and radar astronomy. Among the scientists interested in the site was Frank Drake, one of the founders of the SETI program, who successfully proposed a project to the National Science Foundation to replace the military’s wire mesh dish with a smoother surface of 38,788 shaped aluminum panels, enabling it to detect signals of higher frequency. Thus the non-military, extraterrestrial-searching Arecibo was born. Federal funding for SETI (from NASA) later stopped however, and the dish is only sometimes used for this function today. Despite the high cost of operating the remote facility, it is still managed by Cornell, used primarily for atmospheric and ionospheric studies. "Sometimes, up to three days a week, the radio telescope is shut down because technicians essentially have to beat back the jungle," says Mike Nolan, a planetary radar scientist at the site.
Recent upgrades are improving the capabilities of the observatory, including new mirrors and receivers at the focal point of the dish, contained in a six-story structure suspended 450 feet above the bottom of the bowl. And, like at Biosphere 2, another unusual research property owned by Cornell, tourism is encouraged at Arecibo, spurred on by its appearances in films such as Contact, an adaptation of the Carl Sagan book about his search for ET, where the telescope played itself in a starring role.
Kitt Peak, Arizona: A Cluster of Portals for the Naked and Aided Eye
"QUIET, DAY SLEEPERS," READS A sign on the way into the observatory grounds of Kitt Peak, giving a sense of the inversion of this unusual place, an earthbound gallery of the sky nearly a mile above the Sonoran desert of Arizona. Like the desert creatures that escape the heat of day, many of the scientists here are nocturnal, as this is the place they have come to peer into space along the lines of the visible spectrum, a form of seeing that is best done in the dark.
The mountaintop is an unusual sight: twenty white domes popping out of the terrestrial surface, the largest collection of major optical telescopes in the world. There are 22 optical telescopes and 2 radio telescopes at Kitt Peak, utilized primarily by graduate students and professional astronomers working through universities. The site, officially called Kitt Peak National Observatory, is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation. Also at Kitt Peak is the National Optical Astronomy Observatory, which has a sister site at Cerro Tololo, in Chile.
Many of the individual scopes are operated by partnerships between universities and other organizations, creating a confounding variety of acronyms. The WIYN (Wisconsin, Indiana, Yale, NOAO) telescope, for example, is one of four imaging telescopes on Kitt Peak able to directly view the cosmos through an eyepiece. Most of the other telescopes are spectrographic, automatically collecting light emitted by the elements which make up stars and other celestial entities. This information feeds directly into the datastream for analysis, and can be outputted later as "image" if necessary.
Also at Kitt Peak are two solar telescopes, including the dramatic-looking McMath-Pierce solar telescope (the largest of its kind in the world), and a 25 meter radio telescope which is part of the Very Long Baseline Array (VLBA), a series of 10 similar devices across the USA which collectively track celestial objects. Several of the telescopes are of historical interest, such as the Kitt Peak Vacuum Telescope, built in 1973 to support Sky Lab.
Kitt Peak began as an idea as the space program got underway in the 1950s, when parallel opportunities opened for the field of astronomy. Astronomers petitioned for a consolidated national observatory that would be accessible to many researchers. 6,875 foot tall Kitt Peak was chosen from among 11 other mountains considered in Arizona, California and New Mexico, mostly because of the perfect weather for looking skyward – little light pollution or air turbulence, clear days, low humidity. Other optical observatories near urban areas have been rendered less effective because of excessive light and air pollution, such as Mount Wilson Observatory in Los Angeles and Mount Palomar near San Diego. Except for the frequent summer lightning storms (Kitt Peak is said to be struck by lightning more than any other observed place in the United States except Orlando, Florida), nighttime on Kitt Peak is dark and clear. Ground light sources in nearby Tucson are kept dim by law so as not to interfere with the observatory's mission.
Kitt Peak lies within the Tohono O'odham Reservation, which was originally created by the U.S. government in 1874, with land added and taken away by successive administrations over a period of 50 years. Now it is the second largest reservation in the US, with four non-contiguous segments totalling 2.7 million acres. When first approached by the federal government about the site, the Tohono O’odham refused to give up the peak they considered sacred. The tribe eventually acquiesced, apparently after tribal leaders were shown the proximity of the heavens when viewed through a telescope. The land was leased to the U.S. in perpetuity, under the important condition that the observatory would be used for astronomy only, and not military purposes.
The telescopes on Kitt Peak are in high demand - astronomers apply for time slots a year or more in advance, and are occasionally disappointed by bad weather. Several of the telescopes can be visited, and tours are given daily.
