  In 1974 Hulse and Taylor discovered the binary pulsar. At that time Prof.
Dyson was visiting the Max Planck Institute for Physics at Munich, where I was
also working. He initiated a number of discussions on this object. During them
it occurred to me that this system could be used to test Geodetic Precession in
Einsteins theory, which, even after years of work by the Stanford gyroscope
expt, had remained a challenge. I showed some preliminary calculations to Prof
Dyson and he encouraged me to do a more refined job. To be applicable to the
binary pulsar, one needed to generalise the general relativistic calculations
to beyond the so called test particle assumption. Barker and OConnell had
obtained such a result from analysing the gravitational interactions of spin
half Dirac fermions in linearized spin 2 theories of gravitation. With C.F. Cho
I produced a purely classical calculation, using Schwingers Source theory.
Boerner, Ehlers and Rudolf confirmed this result with their general
relativistic calculations shortly after. With V. Radhakrishnan, I gave a
detailed model for the pulse width and polarization sweep as a means of
observing this effect. All throughout Prof. Dyson was supportive with reading
the manuscripts and his critical comments. In 2005, coincidentally the
centennial of the Annus Mirabilis(1905), Hotan, Bailes and Ord observed this in
the binary pulsar J1141 6545.
