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Astronomy 345 Instrumentation Here we concentrate on the non-optical side of astronomical
instrumentation. In particular, we consider the methods and techniques
used in radio astronomy, taking the student through many of the major topics
in this broad field, from antenna theory to the search for extraterrestrial
intelligence (SETI).
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Course details and lecture notes |
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Introduction to radio astronomy: Revision of fundamentals. Flux density and sky 'brightness'. Blackbody radiation and effective temperature. The Rayleigh-Jeans Law. Energy received from an extended source. Examples of radio sources.
| lecture notes: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
Antennas and noise: Antenna power patterns and beams. Effective area and aperture efficiency. Antennas as resistances and Nyquist's Theorem. Antenna temperature and its relationship to sky brightness temperature. Antenna directivity and gain. The Reciprocity Theorem.
| lecture notes: | 1 | 2 | 3 | 4 | 5 | 6 | 6a | 7 | 8 | 9 | 10 |
Types of antennas: dipoles and horns. Cassegrain feeds. Effects of surface irregularities. Simple antenna arrays (discrete and continuous). Fourier transform relationships.
| lecture notes: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
Radio telescope receivers: The design of a "total power" radio telescope. Mixing, filtering and square-law detection. Minimum detectable temperature and flux density. System temperature. The equation of radio astronomy. Beam chopping.
| lecture notes: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
Interferometry and coherence: The need for resolution. Coherence, complex fringe visibility and the van Cittert-Zernike Theorem. Fourier transforms and the (u,v) plane. Phase-switched interferometer and digital correlation interferometer. VLBI, GPS and the use of interferometers in geodesy.
| lecture notes: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
Aperture synthesis: Imaging interferometers. Path compensation and fringe stopping. Earth rotation aperture synthesis. (u,v) plane coverage and the idea of image reconstruction. The VLA and MERLIN as examples.
| lecture notes: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
SETI: Design considerations and principles behind the search for extraterrestrial intelligence. Bandwidth and sensitivity constraints.
| lecture notes: | 1 | 2 | 3 | 4 | 5 | 6 |
Cosmic rays: Synchrotron radiation. The connection between power-law radio spectra and cosmic rays.
| lecture notes: | 1 | 2 | 3 | 4 | 5 | 6 |
Due to the limited availability of the relevant textbooks, and their prices, the lecture notes will be as complete as possible. However the following books cover all or some of the course well, and you may find it useful to consult them in the library:
Further reading: A graduate-level summer school on radio astronomical imaging is held regularly at the VLA. The slides from a recent meeting can be found here.
