William H. Jefferys
Encyclopedia
William H. Jefferys (born 1940) is an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...

. He is a Harlan J. Smith Centennial Professor of Astronomy (Emeritus) of astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 at The University of Texas at Austin
University of Texas at Austin
The University of Texas at Austin is a state research university located in Austin, Texas, USA, and is the flagship institution of the The University of Texas System. Founded in 1883, its campus is located approximately from the Texas State Capitol in Austin...

, and an adjunct professor of statistics
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....

 at the University of Vermont
University of Vermont
The University of Vermont comprises seven undergraduate schools, an honors college, a graduate college, and a college of medicine. The Honors College does not offer its own degrees; students in the Honors College concurrently enroll in one of the university's seven undergraduate colleges or...

.

Jefferys specialized in astrometry
Astrometry
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...

, celestial mechanics
Celestial mechanics
Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics is a subfield which focuses on...

 and astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...

, including the kinematics
Kinematics
Kinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....

 and dynamics
Dynamics (mechanics)
In the field of physics, the study of the causes of motion and changes in motion is dynamics. In other words the study of forces and why objects are in motion. Dynamics includes the study of the effect of torques on motion...

 of astronomical bodies. He has also worked in the field of Bayesian statistics
Bayesian statistics
Bayesian statistics is that subset of the entire field of statistics in which the evidence about the true state of the world is expressed in terms of degrees of belief or, more specifically, Bayesian probabilities...

, particularly with astronomical applications.

Jefferys was the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...

 Astrometry Science Team leader, and participated in the project that repaired the Hubble Space Telescope after the discovery of its initial optic
Optic
Optic may mean:* optic, a British term for a device for dispensing fixed amounts of alcoholic spirits* Optics, the study of the behavior and properties of light* An optical element or component, such as a lens, prism, or mirror...

al defect.

Jefferys served as chairman of The University of Texas Department of Astronomy from 1994 to 1998. He retired from the University of Texas in 2004 and moved to Vermont in 2005, where he accepted an appointment as adjunct professor of statistics
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....

 at the University of Vermont
University of Vermont
The University of Vermont comprises seven undergraduate schools, an honors college, a graduate college, and a college of medicine. The Honors College does not offer its own degrees; students in the Honors College concurrently enroll in one of the university's seven undergraduate colleges or...

.

External links

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