music and stars

First thing, I met with Schiminovich (Columbia), Mohammed (Columbia), and Dun Wang (NYU) to discuss our GALEX imaging projects. We decided that it is time for us to produce titles, abstracts, outlines, and lists of figures for our next two papers. We also realized that we need to produce pretty-picture maps of the plane survey data, and compare it to Planck and GLIMPSE and other related projects.

I had a great lunch meeting with Brian McFee (NYU) to catch up on his research (on music!) and ask his advice on various time-domain projects I have in mind. He has new systems to recognize chords in music, and he claims higher performance than previous work. We discussed time-series methods, including auto-encoders and HMMs. As my loyal reader knows, I much prefer methods that deal with the data probabilistically; that is, not methods that always require complete data without missing information, and so on. McFee had various thoughts on how we might adapt methods that expect complete data for tasks that are given incomplete data, like tasks that involve Kepler light curves.

streams, rhythm, geometry

At group meeting, Ana Bonaca (Yale) told us about inferring the potential and mass distribution in the Milky Way using pairs of cold stellar streams. She seems to find—even in the analysis of fully simulated data sets—somewhat inconsistent inferences from different streams. They aren't truly inconsistent, but they look inconsistent when you view only two parameters at a time (because there are many other nuisane parameters marginalized out). She shows (unsurprisingly) that radial velocity information is extremely valuable.

Brian McFee (NYU) talked about measuring rhythm in recorded music. Not tempo but rhythm. The idea is to look at ratios of time lags between spectrogram features (automatically, of course). He showed some nice demonstrations with things that are like "scale transforms": Like Fourier transforms but in the logarithm of frequency.

In the afternoon, Bonaca, Foreman-Mackey, and I discussed the relationships between dynamics and geometry and statistics. I gave a very powerful argument about why sampling is hard in high dimensions, and then immediately forgot what I said before writing it down. We discussed new MCMC methods, including Foreman-Mackey's proposals for Hamiltonian MCMC in an ensemble.

dotastronomy, day 3

The day started with the reporting back of results from the Hack Day. There were many extremely impressive hacks. The stand-outs for me—and this is a very incomplete list—were the following: Angus and Foreman-Mackey delivered two Kepler sonification hacks. In the first, they put Kepler lightcurves into an online sequencer so the user can build rhythms out of noises made by the stars. In the second, they reconstructed a pop song (Rick Astley, of course) using lightcurves as fundamental basis vectors. This just absolutely rocked. Along similar lines, Sascha Ishikawa (Adler) made a rockin' club hit out of Kepler lightcurves. Iva Momcheva did a very nice analysis of NASA ADS to learn things about who drops out of astronomy post-PhD, and when. This was a serious piece of stats and visualization work, executed in one day. Jonathan Fay (Microsoft) implemented the Astrometry.net API to get amateur photographs incorporated into World-Wide Telescope. Jonathan Sick (Queens) and Adam Becker (freelance) built tools to make context-rich bibliographic and citation information that could be used to build better network analysis of the literature. Stuart Lynn (Adler) augmented HTML with tags that are appropriate for fine-grained markup for scientific publications, with the goal of making responsive design for the scientific literature while preserving scholarly information and referencing. Hanno Rein (Toronto) built a realistic three-dimensional mobile-platform fly-through system for the HST 3D survey.

After these hacks, there were some great talks. The highlights for me included Laura Whyte (Adler) talking about their incredibly rich and deep programs for getting girls and under-represented groups to come in and engage deeply at Adler. Amazingly well thought out and executed. Stefano Meschiari (UT) blew us away with a discussion of astronomy games, including especially "minimum viable games" like Super Planet Crash, which is just very addictive. He has many new projects and funding to boot. He had thoughtful things to say about how games interact with educational goals.

Unconference proceeded in the afternoon, but I spent time recuperating, and discussing data analysis with Kelle Cruz (CUNY) and Foreman-Mackey.

dotastronomy, day 2

Today was the Hack Day at dotastronomy. An incredible number of pitches started the day. I pitched using webcam images (behind a fisheye lens) from the Liverpool telescope on the Canary Islands to measure the sidereal day, the aberration of starlight, and maybe even things like precession and nutation of the equinoxes.

I spent much of the day discussing and commenting on other hacks: I helped a tiny bit with Angus and Foreman-Mackey's hack to sonify Kepler data, I listened to Jonathan Fay (Microsoft) as he complained about the (undocumented, confusing) Astrometry.net API, and I discussed testing environments for science with Arfon Smith (github) and Foreman-Mackey and others.

Very late in the evening, I decided to get serious on the webcam stuff. There is an image every minute from the camera and yet I found that I was able to measure sidereal time differences to better than a second, in any pair of images. Therefore, I think I have abundant precision and signal-to-noise to make this hack work. I went to bed having satisfied myself that I can determine the sidereal period, which is equivalent to figuring out from one day's rotation how many days there are in the year. Although I measured the sidereal day to nearly one part in 100,000, my result is equivalent to a within-a-single-day estimate for the length of the year of 366.6 days. If I use more than one image pair, or span more than one day in time, I will do far, far better on this!

dotastronomy, day 1

Today was the first day of dotastronomy, hosted by the Adler Planetarium. There were talks by Arfon Smith (Github), Erin Braswell (Open Science), Dustin Lang (Astrometry), and Alberto Pepe (Authorea). Smith made a lot of parallels between the open collaborations built around github and scientific collaborations. I think this analogy might be deep. In the afternoon, unconference was characteristically diverse and interesting. Highlights for me included a session on making scientific articles readable on many platforms, and the attendant implications for libraries, journals, and the future of publishing. Also, there was a session on the putative future Open Source Sky Survey, for which Lang and I own a domain, and for which Astrometry.net is a fundamental technology (and possibly Enhance!). There were many good ideas for defining the mission and building the communities for this project.

At coffee break, Foreman-Mackey and I looked at McFee's project of using Kepler light-curves as basis vectors for synthesizing arbitrary music recordings. Late at night, tomorrow's hack day started early, with informal pitches and exploratory work at the bar. More on all this tomorrow!

single transits, group meeting, robot DJs

The day started with a discussion with So Hattori about finding single transits in the Kepler data. We did some research and it seems like there may be no clear sample in the published literature, let alone any planet inference based on them. So we are headed in that direction. In group meeting, Foreman-Mackey told us about his approach to exoplanet search, Goodman told us about his approach to sampling that uses (rather than discards) the rejected likelihood calls (in the limit that they are expensive), and Vakili told us about probabilistic PSF modeling. On the latter, we had requests that he do something more like train and test.

A fraction of the group had lunch with Brian McFee (NYU), the new Data Science Fellow. McFee works on music, from a data analysis perspective. His past research was on song selection and augmenting or replacing collaborative filtering. His present research is on beat matching. So with the two put together he might have a full robot DJ. I have work for that robot!