The Townes Perspective

To best understand science or religion, we must use all of our human resources

Mid-infrared interferometry with high spectral resolution

The Infrared Spatial Interferometer (ISI) is a three telescope interferometer system that operates near 11 microns wavelength using heterodyne detection with CO2 lasers as local oscillators. Stellar measurements have been made using consistent instrumentation for 20 years, allowing comparisons of stellar sizes of red giant and Mira stars over time intervals which are long in comparison to stellar luminosity periods. Recent visibility and closure phase measurements of the star Betelgeuse have been fitted to simple image models and these results have been added to the 17 year record of stellar observations. A new area of investigation of stellar properties at very high spectral resolution will begin in the 2010-2011 observing season. The design of a new digital spectrometer-correlator system is discussed. This system will obtain visibility measurements on-and-off individual spectral lines and the continuum, simultaneously

Training of Instrumentalists and Development of New Technologies on SOFIA

This white paper is submitted to the Astronomy and Astrophysics 2010 Decadal Survey (Astro2010)1 Committee on the State of the Profession to emphasize the potential of the Stratospheric Observatory for Infrared Astronomy (SOFIA) to contribute to the training of instrumentalists and observers, and to related technology developments. This potential goes beyond the primary mission of SOFIA, which is to carry out unique, high priority astronomical research. SOFIA is a Boeing 747SP aircraft with a 2.5 meter telescope. It will enable astronomical observations anywhere, any time, and at most wavelengths between 0.3 microns and 1.6 mm not accessible from ground-based observatories. These attributes, accruing from the mobility and flight altitude of SOFIA, guarantee a wealth of scientific return. Its instrument teams (nine in the first generation) and guest investigators will do suborbital astronomy in a shirt-sleeve environment. The project will invest $10M per year in science instrument development over a lifetime of 20 years. This, frequent flight opportunities, and operation that enables rapid changes of science instruments and hands-on in-flight access to the instruments, assure a unique and extensive potential - both for training young instrumentalists and for encouraging and deploying nascent technologies. Novel instruments covering optical, infrared, and submillimeter bands can be developed for and tested on SOFIA by their developers (including apprentices) for their own observations and for those of guest observers, to validate technologies and maximize observational effectiveness.Comment: 10 pages, no figures, White Paper for Astro 2010 Survey Committee on State of the Professio

Souvenirs de la genèse du laser

Dans ce texte, Charles Hard Townes, inventeur du maser et père du laser optique, présente ses souvenirs de cette épopée. C.H. Townes a reçu (avec N.G. Basov et A.M. Prokhorov) le prix Nobel de physique en 1964, pour « des travaux de recherche fondamentale en électronique quantique, qui ont conduit à la construction d’oscillateurs et d’amplificateurs, basés sur le principe du maser-laser »

Nuclear quadruple moments and nuclear shell structure /

Work performed at the Brookhaven National Laboratory."AECU-679"Includes bibliographical references.Mode of access: Internet