GPCA Overview

Description

Located five miles north of Hayden, Nebraska, the Great Plains Cruciform Array (GPCA) is a radio observatory equipped with 22 radio telescopes deployed in a cruciform arrangement. Nine of these telescopes are stationary 10.5-meter Leighton dishes, twelve are movable 25-meter dishes, and the largest is a 50-meter steerable dish located atop the main control tower. The facility includes an administration building, a dormitory, and a sprawling complex of workshops. Two additional buildings are no longer entirely functional—a small, optical observatory that dates from the 1950s, and a visitor center which closed during the COVID pandemic and never reopened.

History

The GPCA is built on a desolate section of prairie with a storied connection to science. The land was originally donated to the University of Nebraska in 1904 by Shiloh Hayden, a wealthy rancher and amateur meteorologist with connections to the University. The University used the land to study geology, meteorology, and prairie ecosystems, and to conduct various projects under the aegis of the Agricultural College. Over the years the “Hayden Prairie Trust” developed a reputation for excellent weather conditions and unusually clear skies.

Swezey-Minnich Observatory (SMO)
In 1949 the site was selected to host an observatory funded by a consortium of University donors and managed by the Physics and Engineering departments. The Swezey-Minnich Observatory was completed three years later. Designed to match the art deco style of the Nebraska State Capitol, the SMO was equipped with an Alvan Clark 18” refracting telescope. First light was achieved on 20 March 1952 by Kevin Ross, the university astronomer appointed as the first director of the SMO, who captured a stunning image of Pluto as it swung by Epsilon Leonis at 9:12 PM. Unfortunately, when posing for a publicity photo, Ross dropped the developed plate and shattered it irreparably. It was an omen of the observatory’s unhappy future.

Hayden Radio Observatory (HRO) / Shiloh Hayden Dual Observatory (SHADO)
In 1959 the National Science Foundation decided Hayden was the perfect location for a radio telescope. The Hayden Radio Observatory was completed in 1963 with assistance from MWUA, a consortium of Midwest universities and colleges led by the University of Nebraska. The HRO consisted of a control tower designed in the same art deco fashion as the Swezey-Minnich Observatory, topped by a 50-meter mesh antenna simply named the Hayden Radio Telescope. The SMO and the HRO were collectively operated as the Shiloh Hayden Dual Observatory (SHADO). First light was received the morning of 22 November 1963 by Ambrose Tillinghast, the first director of SHADO. A few hours later, President Kennedy was assassinated in Dallas, an event that—to put it mildly—eclipsed the news out of Hayden.

Great Plains Cruciform Array (GPCA)
On 17 December 1969 SHADO was selected to host the Great Plains Cruciform Array, an NSF/NRAO project in cooperation with Associated Universities, Inc., and built with generous contributions from Perry Legrasse Brendan. A Louisiana oil tycoon interested in SETI research, “Commodore” Perry put up $15 million to defray the GPCA’s $75 million budget. Construction began in 1972, and Brown University astronomer Henry Annesley was appointed the GPCA’s first director. Although “first fringes” were achieved on 4 July 1976 to honor the Bicentennnial, the GPCA wouldn’t be formally completed until 28 March 1979.

The Ross Reflector
When Hayden was selected for the GPCA, the telescope at the SMO was updated to a 24” Boller & Chivens f/13.5 Ritchey-Chrétien Cassegrain reflector. The new telescope was named the Ross Reflector in honor of the observatory’s first director. The observatory continued to function until 1986, when it was permanently shut down after a series of unfortunate events. (See “Location—Swezey-Minnich Observatory” for details.)

HRT Upgrade
During construction of the GPCA in the 70s, the Hayden Radio Telescope was updated. The outer mesh panels were replaced by perforated aluminum panels, and the inner aluminum plating was upgraded to improve the telescope’s focusing capabilities.

2009–2010 Renovations
From 2009–2010, Director Sarah Potter oversaw a series of renovations to the GPCA. Designed to “bring the GPCA into the twenty-first century,” the renovations originally encompassed the entire facility, from modernizing the HRO control tower to installing a new reflector in the SMO. Unfortunately, a series of merciless budget cuts forced a reduction of scope. In the end, the renovations were restricted to HRO’s control room, server room, director’s office, conference rooms, lower lounges, and atrium; along with the tower’s windows and exterior surfaces. The Hayden Radio Telescope had its inner plating extended and was rechristened the Tillinghast Radio Telescope. The “old HRO tower” was formally named the Annesley-Ross Tower (ART). The planned makeovers of the administration building, visitor center, and dormitory were reduced to necessary technological updates. Rather than reopen the SMO, the building was cleaned and refurbished, transformed from a dubious storage space into a museum-like seminar hall.

2020 Shutdown
In April 2020, the visitor center and dormitory cafeteria were closed for COVID. A dozen supporting GPCA personnel were laid off. Neither building has re-opened since the pandemic. With the NRAO focused on updating the VLA and the Trump Administration’s budget cuts, it’s unlikely the GPCA will reopen these facilities any time soon, let alone “complete” the 2010 renovations.

Previous Directors
1952–1959. Kevin Ross (SMO)
1959–1960. Arnold Hird, Jr. (SMO)
1960–1969. Ambrose Tillinghast (SHADO)
1969–1970. Henry Valk (SHADO)
1968–1972. Winston St. John Lowell (SHADO)
1972–1986. Henry Annesley (GPCA)
1986–1987. Benjamin Savage (Acting Director)
1987. Patricia Marie McMillan
1992–1995. Alistair Peck
1995–2000. K. Perotine Jekyll
2000–2007. Dalton Louck
2007–2012. Sarah Potter
2012–present. Gerald Neal

Bible Black > Locations
[Back to Wagon Train Diner | Bible Black TOC | Forward to Antennas & Workshop]

Author: A. Buell Ruch (Based on work by Kevin A. Ross)
Last Modified: 2 February 2026
Email: quail (at) shipwrecklibrary (dot) com
Bible Black PDF: [TBD]