Karl Jansky and Grote Reber started the field of radio astronomy.
One by serendepity and one by a deliberate decision.  Following
World War II English, Canadian and Australian physicists and engineers
who were demobbed started radio astronomical research.  From an
astronomical perspective the importance of studying the heavens at
radio wavelengths was recognized early on by Jan Oort in the
Netherlands, Jessie Greenstein at Caltech and Harold Weaver at
Berkeley.  Jessie persuaded Caltech authorities to start a major
program in radio astronomy (first at Palomar and then at OVRO when
the importance of interferometry became clear). John Bolton was
invited from Australia and he founded the Owens Valley Radio
Observatory which trained a large fraction of early US radio
astronomers: Clark, Kellerman, Radhakrishnan, R. Wilson (who went
on to win a Nobel Prize), Rogstad, Ed Fomalont and Al Moffet.

Greenstein's achievements go well beyond making Caltech a power house
not only in radio astronomy but in astronomy. We are after all the
best astronomy department in the world. Once a year we remember
Jessie by inviting a great leader, a visionary in astronomy to
come and spend some time with us and remind us of Jessie.

In my view there are six giants who define modern radio
astronomy and today we will be recognizing Sandy Weinreb who
is one of these giants. After having delieberated for
quite some time, I recall it it was about a minute or so,
we chose Sandy Weinreb as this year's Greenstein Lecturer. 

Sandy Weinreb obtained his PhD in 1963 from the Research Laboratory
for Electronics, MIT and the topic was "A Digital Spectral Analysis
Technique and its application to Radio Astronomy". This was
the world's first digital autocorrelation spectrometer. With this
he searched for the hyperfine structure of Deuterium (327 MHz) and
placed strong upper limits. Following his PhD the spectrometer was
used by Sandy, Alan Barrett, Lit Meeks and J. C. Henry in the
successful detection of interstellar OH, the first radio observation
of an interstellar molecule.  This was undertaken at the Millstone Hill
84-foot telescope of MIT's Lincoln Laboratory.

Digital correlators now form the
backbone of radio astronomy. 

Sandy then joined the nascent NRAO and rose to become the head of
Electronics Division & Assistant Director. During his 23 years 
at NRAO he pioneered the use of low noise cooled amplifiers.
He was the architect for the electronics systems of the Very Large Array.

He then had a stint in industry: Lockheed Martin Laboratories and 
then returned to where he should have been in the first place -- Caltech.
Somewhere in between Sandy developed MMIC (Monolithic Microwave
Integrated Circuit) amplifiers -- another cornerstone of modern
astronomy. 

Sandy is still young at heart and has more drive then most of us.
He is a major driver for the SKA in US and at the samer time he
is advising students in wide band amplifiers, investigation of
Fast Radio Bursts and partnering with Greg Hallinan in the LWA.

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John Bolton, Martin Ryle, Robert Dicke, Alan Barrett, 
Sandy Weinreb, Barry Clark and arguably Charlie Townes.

Oort, Weaver & Greenstein
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