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Telescopes for Education

In Green Bank, West Virginia, two of our radio telescopes are used by schools, clubs, and citizen scientists to carry out fascinating scientific research.

The 40-foot transit telescope has its own control building set underground. It has hosted years of students, teachers, and astronomy enthusiasts for observing projects. These visiting observers either stay in the bunkhouse or pitch tents right next to the dish.

The 20-meter radio telescope is robotically controlled by members of the SKYNET program, an astronomy education project run out of the University of North Carolina in Chapel Hill.

The Green Bank site of the National Radio Astronomy Observatory was our first radio astronomy facility. For over 50 years, thanks to its State and Federal Radio Quiet Zones, Green Bank has been a popular testing ground for new and wonderful telescope designs. In addition to our active research telescopes, we have dozens of unique and sometimes antique antennas dotting the 2700-acre site.

Thankfully, we have a strong culture of reuse, and rarely do we mothball any disused telescopes for very long. Two of our radio telescopes, the 40-foot and the 20-meter, are now full-time educational instruments used by students around the country. But they once had quite an exciting past.

40-foot Telescope

In 1961, a 40-foot telescope was ordered from Antenna Systems, Incorporated and delivered to our growing observatory in Green Bank, West Virginia. This inexpensive aluminum telescope took only two days to set up and began observations on December 14, 1961.

The 40-foot telescope can only move in one direction, up and down. It relies on the Earth’s rotation to swing it underneath the space objects it observes. With a control system designed and built by NRAO staff, on February 1, 1962 the 40-foot became the world’s first fully automated telescope.

The 40-foot provided us with an unmanned observing program focused solely on radio sources whose brightness changes over time. Its five-year mission observed eight radio sources every day: 3C 48, 3C 144 (Taurus A, aka Crab Nebula), 3C 218 (Hydra A), 3C 274 (Virgo A), 3C 295, 3C 358, 3C 405 (Cygnus A), and 3C 461 (Cas A).

After sitting mostly idle for nearly two decades, the 40-foot was recommissioned in 1987 as an educational telescope and has been in use ever since. Students ranging from 5th graders to graduate students use the telescope to investigate the radio universe. The Education in Radio Astronomy (ERIRA) one-week summer workshop comes to Green Bank every year to use the 40-foot. Teachers from Radio Astronomy Research Enhancing Coordinated and Thematic Science (RARE CATS) complete extensive research projects using the 40-foot, and Chautauqua Short Course participants have access as well. In addition, amateur astronomers routinely make use of this telescope.

Stats for the 40-meter telescope

Receiver: 1350 MHz to 1430 MHz

We repurposed the Tatel Telescope’s 1960 feed that was created by Frank Drake for Project Ozma, the world’s first scientific search for extraterrestrial intelligence.

The spectrometer of the 40-foot comes from our old 300-foot telescope that collapsed in 1988.

20-Meter Telescope

The 20-meter telescope arrived as a guest at our site in Green Bank, West Virginia in 1994. The telescope was built by RSI and installed by the US Naval Observatory (USNO) as a new antenna for their Earth observing programs.

Engineers in Green Bank built its receiver and installed it on January 11, 1995. The 20-meter observed with other telescopes to test its systems during the next few months, but had to give up some of its parts to help a twin 20-meter in Hawaii. By October 1995, the 20-meter was in regular operation by the USNO.

The National Earth Orientation Service (NEOS) telescope network and the USNO Navy Network (NAVNET) use antennas around the world to measure small wobbling motions of the Earth's polar axis and irregularities in the Earth's rate of rotation with reference to positions of quasars (distant bright explosions in nuclei of galaxies). Quasars are the most distant point-like radio sources known, and therefore form a good set of stable reference points.

Other telescopes participating in the NEOS network are: Kokee Park Geophysical Observatory (Kauai, Hawaii); Gilmore Creek Geophysical Observatory (Fairbanks, Alaska); Wettzell, Germany; Fortaleza, Brazil; and Algonquin Park (Ontario, Canada). This telescope network is by the International Earth Rotation Service (IERS) to supply data needed for high accuracy world-wide navigation systems.

The data are also used for studies of continental drift and of atmospheric and oceanic currents, in collaboration with the NASA Geodetic VLBI program. Prior to the completion of the 20-meter, these geodetic VLBI experiments had been using telescope 85-3, part of the Green Bank Interferometer.

The USNO shut down their use of the 20-meter in June 2000 when their experiments were completed.

In 2008, an L-band frequency array receiver feed, destined for use on the Robert C. Byrd Green Bank Telescope, was installed and tested on the 20-meter. It successfully observed the radio emissions around the famous Cygnus X-1 black hole complex.

The 20-meter was refurbished in 2012 as the first radio telescope in the SkyNet robotic telescope network project run out of the University of North Carolina, Chapel Hill. Via Internet remote control, students use the 20-meter to observe the invisible Universe from their classrooms.

Stats for the 20-meter Telescope

Height: 84 feet
Weight: 150 tons
Receivers: 1.8 GHz and 8 to 10 GHz at the prime focus
Slew Speed: 2 degrees per second, each axis.
Surface Accuracy: 0.8 mm rms.
Geodetic Position: 38 26'12.661" N.Lat, 79 49'31.865" W.Long.

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