[Doc Ewen looks into the horn antenna, 1950]
Image courtesy of Doc Ewen


Harvard Cyclotron: 1948-1951

Detection of HI Line: 1951

Harvard 24ft and 60ft and NRAO founding: 1952-1956

1950s and 1960s: Two Roads that Crossed

Microwave & Millimeter Wave Applications in the 1970s and 1980s

Mm Wave Radiometry in the 1990s

May 2001 visit to NRAO Green Bank



[Doc Ewen and horn antenna, 2001]
Image courtesy of Doc Ewen

Doc Ewen: The Horn, HI, and Other Events in US Radio Astronomy

by Doc Ewen, © 2005


The technology revolution of the 20th century is continuing unabated into the 21st century. The automobile and the airplane combined with wireless communication set the stage for a technological explosion as we came out of World War II with radar, jet aircraft, nuclear energy and a host of electronic devices. The 1950s saw the dawn of solid state electronics and computer technology, which spawned the Internet and the Web. Man orbited the earth and we were on our way to the moon. Suddenly anything seemed possible. The vacuum tube had lasted a few short decades before the transistor arrived on stage in 1951. The "Rad Lab" series became the bible of the electrical engineer. Surplus World War II antennas, transmitters and receivers were abundant and the Rad Lab cook book showed the inquisitive the details of "how to". TV, followed a few decades later by the ubiquitous cell phone, changed our lives forever.

This cauldron of burgeoning technology captured the imagination of many astronomers in the U.S., England, The Netherlands, and Australia, where radio astronomy was moved center stage from the trials of infancy spurred by the inquisitive Jansky and Reber.

There is little doubt that the early post-War years of U.S. radio astronomy benefited from U.S. Department of Defense investment in applications that used the same or similar instrumentation. The Polaris radio star sextant, needed to provide all weather navigation, was the world’s largest millimeter radio telescope at the time. Much was learned that could not be shared at the time with the radio astronomy community. The Polaris Sextant receiver found its way to NRAO, reconfigured so that its original use was not compromised. This is just one of the many examples of the overlapping of interests and funding by Department of Defense and the radio astronomy community.

With the encouragement and ever present support of Ellen Bouton, Archivist at the National Radio Astronomy Observatory, we have chronicled my perception of several exciting decades in the history of radio astronomy and related applications of microwave and millimeter wave radiometric instrumentation.

I am indebted to the several colleagues I have met and enjoyed along the way. Many that I visit and work with today are among those I first met in the 1950s. I would like to thank those who provided a brief perspective of their own, as an added bonus to the work presented here.

With the tools we have today, and those being developed, the future of radio astronomy is limitless. There is a special flavor, however, to reminiscing about the past and recalling how things were in "the old days".

Doc Ewen
July 2005

Modified on Monday, 18-Jul-2005 11:42:50 EDT by Ellen Bouton