[Discontinued] Radio Interferometry - anjavdl/PHY517_AST443 GitHub Wiki
Note: this lab is now unlikely to work, because of too many satellites in the sky that contaminate the signal.
Measuring the angular diameter of the Sun.
Michelson interferometry is a technique with broad applications in both physics and astronomy, and is used to date to directly measure stellar diameters. The Sun is a marginally resolved source for our home-built Stony Brook radio telescope when viewed in single-dish mode, but is well resolved when observed interferometrically. Compare an intensity scan of the Sun to that of a known point source (a geostationary TV satellite) in single-dish mode and infer the Sun's angular diameter. Then repeat the experiment with the interferometer, recording the Sun's and the satellite's visibility amplitudes as a function of baseline for several different interferometer baselines. Your interferometric measurements should yield a much more accurate solar diameter.
Locus of geosynchronous satellite positions seen from Stony Brook
Solar Positions from US Naval Observatory
Scheduling
Although radio astronomy can be done when it's cloudy, it needs to be clear enough (at the beginning of the lab) that you can see the shadow of the Sun. You therefore need to choose one primary observing data, as well as two back-up days. The lab can take long; you should start setting up at 8am.
Data Analysis
Python script that simulates the observation of a uniform disk with a Gaussian PSF