Scientific Colloquium
March 23, 2016, 3:30 p.m., Building 3 Auditorium

"Hipparcos, Hubble Space Telescope, and Gaia: A Golden Age of Astrometry"

I will describe the Gaia astrometric mission, how it works, on-orbit status, and the volume and precision of the expected results. In order to better appreciate the magnitude and importance of these results, I describe how astrometry is done with the Hubble Space Telescope, and summarize some of our 100-200 microsecond of arc precision results. Gaia will produce 10 microsecond of arc precision results, yielding a three dimensional map of our Galaxy with unprecedented precision, accuracy, and detail. Gaia should beat its precursor mission, Hipparcos, by a factor of a hundred in precision, and a factor of 10,000 in sheer volume of results.

About the Speaker:

I received my Astronomy Ph.D. in 1972 from Northwestern University. I came to the University of Texas at Austin in 1972. My present position is Senior Research Scientist with McDonald Observatory. In 1977 I became a member of the Hubble Space Telescope Astrometry Science Team. My project responsibilities included designing a Guide Star Selection System for the HST, the basis for the system now in use at the Space Telescope Science Institute. After HST launch in 1990, my astrometric scientific interests have centered on sub-millisecond of arc precision parallaxes (precise distances to stars) and the astrometric characterization of low mass companions to stars (exoplanet masses). My interest in space astrometry led to participation in more than twenty Guest Observer projects with Hubble Space Telescope over the last 20 years, most as Principal Investigator. A few interests outside astronomy include sailing a Catalina 22, reading, walking my ridiculously small dog, and home maintenance.

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