GBO antenna array a test for larger project

the Green Bank Observatory was a test site for a small array of antennas this past summer as part of The Canadian Hydrogen Intensity Mapping Experiment – or CHIME. Photo courtesy of Jill Malusky

Suzanne Stewart
Staff Writer
The Green Bank Observatory is world-renowned for its telescopes – be it the historical Reber Telescope which was painted red, white and blue for West Virginia’s Centennial celebration, or the Green Bank Telescope, the world’s largest fully steerable radio telescope.

The GBO campus is not only the permanent home to multiple telescopes, it is also a testing site for antennas, due to the National Radio Quiet Zone.

The telescopes were recently joined by a small array of nine antennas which were part of a test for a permanent antenna.
The array is part of The Canadian Hydrogen Intensity Mapping Experiment – or CHIME – “a revolutionary new Canadian radio telescope designed to answer major questions in astrophysics and cosmology,” according to the CHIME website.

GBO public relations specialist Jill Malusky explained that the experiment took place this summer.

“It’s an array of antennas, and it was a test to see how viable our site would be for doing the type of science that they’re going to be used for,” she said. “It has to do with tracking [hydrogen mapping in the universe]. There are a few instruments in the United States and Canada that are used for tracking this information about our universe and because of the National Radio Quiet Zone and Green Bank’s location, it was believed that our site would be a great spot to put another one of these instruments.”

Test antennas are common practice when designing a new project or instrument for such a large endeavor and Malusky said Green Bank has been used for many tests through the years.

“It’s not really a new practice,” she said. “What’s interesting is, since Green Bank got started, we were always a location that prototyped or tested ways to use instruments together to do new science. Doing prototypes and testing is not new. I guess maybe that doesn’t make headline news because it’s the work you have to do before you do something bigger and more exciting. It is kind of neat to see these new dishes there.”

The small array of antennas were built at GBO in conjunction with West Virginia University and temporarily installed at GBO for the test.

“They were built there at the observatory,” Malusky said. “WVU is working with this larger international partner to execute this project and those antennas were actually built by staff and faculty from WVU. They came down from Morgantown several times to set up the site, put those antennas together. This was a big part of some graduate students’ work to actually assemble those antennas.”

The design of the antennas was pretty standard, but the instrument they will be replaced by is a little less standard.

“I think that the antennas themselves were sort of off the shelf,” Malusky said. “It was pretty standard which ones they knew they needed to use for this test to collect the data, and they would’ve had to work with the international partner to come up with the right amount of antennas and how to arrange them to make sure they could collect the information in this test pattern correctly.

“It’s not going to be as dramatic an instrument as the GBT in the way that it looks,” she continued. “What’s really interesting is it will kind of look like a half pipe – like for skateboarding – and there are a few of these that exist in Canada and other parts of the U.S.”

The test was a success and Malusky said an Environmental Impact Study has been completed and once the contract is signed, the permanent instrument will be built and installed at GBO.

“We’ve gotten all the permissions to start to build this larger instrument, so that will be coming in 2020-2021,” she said.

Because of the Quiet Zone and the abilities of GBO, it is possible for tests like this to take place and lead to more opportunities for new instruments and research to be done at the site.

“A lot of times, we’re a great place to do a test first because you have a lot less interference than you would in other locations,” Malusky said. “That’s cool that international partners seek us out because they know that we’re a good place to do this work.”

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