- 1968--...
- University of South Florida, Tampa, FL 33620
- 1989--...
- Professor, Department of Mathematics
- 1979--1989
- Associate Professor, Department of Mathematics
- 1973--1979
- Associate Professor, Department of Astronomy
- 1968--1973
- Assistant Professor, Department of Astronomy
- 1975--...
- University of Florida, Gainesville, FL 32611
- 1989--...
- Professor, Department of Astronomy
- 1976--...
- Doctoral Research Faculty
- 1979--1989
- Associate Professor, Department of Astronomy
- 1975--1979
- Associate Professor, Department of Physics and Astronomy
- 1975--1976
- Graduate Faculty
- 1985--...
- National Institute of Standards and Technology,
Gaithersburg, MD 20899,
Mathematician, Center for Computing and Applied Mathematics
- 1962--1968
- Yale University, New Haven, Ct 06520
- 1967--1968
- Research Staff Astronomer
- 1962--1967
- Research Assistant
Carol Williams