Suzanne Stewart
Staff Writer
When it came time to name the 59th Jansky Lecturer, the National Radio Astronomy Observatory didn’t have to look too far. Dr. Ken Kellermann worked for the NRAO in both Green Bank and Charlottesville, Virginia, before retiring five years ago.
There are several reasons why it’s fitting for Kellerman to be selected for the Jansky Lecture. Not only was he a scientist at the NRAO, he had an assistantship in the field of radio astronomy at CalTech, where he worked for John Bolton – who happened to be the first Jansky Lecturer.
Kellermann will return to the Green Bank Observatory Wednesday, November 6, at 7 p.m. to deliver his lecture, “Discovering the Radio Universe.”
Sixty-five years ago, when Kellermann was searching for a field to study for his assistantship at CalTech, he was planning to study physics, but it seems, the universe had different plans for him.
“I was given two weeks to find something interesting and a professor willing to take me on,” he recalled. “I went around and talked with various professors. Everyone I spoke with was very cordial. They took the time to explain their research – I talked to professors working in nuclear physics, atomic physics, low temperature physics and solid-state physics.”
During these discussions, Kellermann said he didn’t find anything interesting, and he felt as though none of the professors were interested in him either.
As the two weeks were coming to a close, someone in the physics department suggested he speak with Professor Bolton who was starting a new radio astronomy project.
“He asked me just two simple questions,” Kellermann said. “He wasn’t interested in what courses I had taken or whether I could solve partial differential equations. He asked me what I knew about electronics, and I told him that I was a radio amateur, I could read circuit diagrams and I knew how to use a soldering iron.
“Then he asked me the key question which I completely misunderstood,” he continued. “Because I misunderstood what he was asking me, I gave him the answer he was looking for. He asked me how I felt about heights.”
Kellermann said he knew the observatory Bolton was building was about 4,000 feet in elevation and the previous year, he spent the summer camping in the Rockies and the Sierras, hiking up to 14,000 feet.
“So, I confidently told him, ‘oh, heights don’t bother me at all,’” he said. “If he had known that I am actually kind of scared of heights, that would have been the end rather than the beginning of my career in radio astronomy.”
Instead, Bolton said there was an empty desk in the next room that Kellermann could use. Kellermann said he was taken aback because he hadn’t yet decided if he wanted to go into radio astronomy.
“I figured, ‘okay, I’ll do this radio astronomy thing for the first semester, that will give me time to find something better,’” he recalled. “That was sixty-five years ago. The past sixty-five years were a fantastic time for radio astronomy. Most of cosmic phenomena we study today, things that we read about in the newspapers or see on TV were unknown back then.”
In 1965, Kellermann joined the staff at the NRAO in Green Bank and was there for 20 years before moving to Charlottesville, Virginia.
“I’ve been at NRAO for my entire professional career,” he said. “After I got my PhD at CalTech, I went to Australia for two years. [Bolton] had himself gone to Australia to be the director of a new facility there and I wanted to continue to work with him, so I went there for two years as a postdoc and then I came to Green Bank.”
During his tenure at Green Bank, Kellermann helped develop a new technique for extending the length of the interferometers. The three 85-foot dish antennas were used together as an interferometer and were usually connected electrically.
“We developed a technique – the data is recorded separately by the different antennas and the recordings have to be precisely synchronized,” Kellermann said. “That’s done by atomic clocks. Then the recordings are brought together and played back together in a computer. You can reconstruct the effect of having a connected interferometer.”
This technique helped pave the way for expanding the observational area across the world, by helping telescopes in different countries to connect to the observatory in Green Bank.
“The 140-foot was used together with other radio telescopes all around the country and all around the world – including the Soviet Union – to do these interferometer experiments,” Kellermann said. “That initiated a lot of exchange between Russian scientists and ourselves.”
Kellermann traveled to Russia once a year for several years, and vice versa with Russian scientists who came to Green Bank, to analyze the data.
The technique was used again, in 2011, with Russian scientists who launched a satellite into space to be used as part of an interferometer with the Green Bank Telescope.
“The Earth is only so big and in order to get higher, bigger antenna separations were needed which enable you to see finer detail in the radio sources in the sky,” Kellermann said. “Our Russian colleagues launched a satellite so you could do interferometry between the satellite and ground antennas. That collaboration concluded about three or four years ago. The satellite was built for a lifetime of five years and actually lasted nearly ten, but it finally started to break down.”
Not only was the collaboration beneficial for the discoveries it made, but also for the relationships and bonds it created.
“It was nice for both sides to really get to know and work with people – for us to get to work with and get to know people from Russia and for people from Russia to get to know us,” Kellermann said.
