[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, © 2003

Slide 48: Two Roads that Crossed in the Wood - Growth of US Radio Astronomy in the 1950s and 1960s

[First radiometer to resolve ozone line profile]

The Ewen-Knight radiometer that was first to resolve an ozone line profile, 101 GHz, 1966. The technique is now used in the ozone global network. Credit: Photo courtesy of Doc Ewen.

The equipment is shown in the former Polaris antenna range house at Ewen Knight (see slide 23), with a World War II search light antenna seen through the window: two roads crossed on an antenna range. The technique was used 15 years later, by Parrish at University of Massachusetts, to explore the ozone hole above Antarctica (e.g. Parrish et al, Science 211: 1158, 1981).

I became interested in ozone when Sam Silver (the fellow who checked my HI horn dimensions) sent a chap to me by the name of Bill Caton for a hands-on course in building millimeter wave spectrometers. Bill and Sam had encountered some problems with the detection of a mmw ozone line, which was part of Bill's doctorate. I wrote a proposal to the Nasa Electronics Research Center (ERC). It was funded by one of the fellows that worked on my "round-the-clock" crew at the Harvard Cyclotron in 1949; in 1965 he was on the NASA ERC staff.

Modified on [an error occurred while processing this directive] by Ellen Bouton