2017-11-09

mixture of factor analyzers; centroiding stars

On this, day four of my Hunstead Lectures, Andy Casey (Monash) came into town, which was absolutely great. We talked about many things, including the mixture-of-factor-analyzers model, which is a good and under-used model in astrophysics. I think (if I remember correctly) that it can be generalized to heteroskedastic and missing data too. We also talked about using machine learning to interpolate models, and future projects with The Cannon.

At lunch I sat with Peter Tuthill (Sydney) and Kieran Larkin (Sydney) who are working on a project design that would permit measurement of the separation between two (nearby) stars to better than one millionth of a pixel. It's a great project; the designs they are thinking about involve making a very large, but very finely featured point-spread function, so that hundreds or thousands of pixels are importantly involved in the positional measurements. We discussed various directions of optimization.

My talk today was about The Cannon and the relationships between methods that are thought of as “machine learning” and the kinds of data analyses that I think will win in the long run.

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