help

How Do You Make An Image From Interferometric Measurements

-- | October 5, 2014

Question: How do you get an image from interference data? I have a decent understanding of interferometry and a basic understanding of Fourier analysis, but I just cannot find an explanation. — Don

Answer: First, let me frame my answer within the contexts of radio interferometers. The basic principles of interferometry are the same whether you are doing it at optical or radio wavelengths. Now, since it is also important to understand how a radio telescope works, let me first point to a very nice tutorial which describes the basic operation of a radio telescope. The Radio Astronomy Tutorial produced by my colleagues at Haystack Observatory is one of the best general descriptions of how a radio telescope works which is written at the level of an undergraduate physics major.

The process used to convert the interference, or “uv” data that an interferometer measures into an image involves, as you mentioned, the Fourier transform. A document, by my colleague Scott Schnee, which I have posted to my Radio Astronomy Tutorials page describes how to transform radio interferometer measurements to images. It is the best description of this process that I am aware of. Hopefully this will provide a good general explanation of the process used to turn interferometric measurements into images.

Jeff Mangum

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