The Étude Sky

Twenty-four études, charted as stars on the circle of fifths. Fifteen keys hold all twenty-four, so some stars are double and one is triple, and the order of publication traces two asterisms across the sky.

“Nature always wears the colors of the spirit.”
Ralph Waldo Emerson, Nature (1836)

The full cycle · 62 min

The plates

Twenty-four polar plots

Each plate is drawn from its recording by one set of rules. Position angle is pitch class on the circle of fifths; distance from the centre is time; every point is a note as it is struck. Each pitch class keeps its colour from the wheel, laid where and when it sounds, and gold joins the strongest notes.

Notes

A sky of my own

When I look up at the night sky, I think of Chopin’s études. This chart is the picture that forms in my mind: each étude a star, placed by its key, and each a plate drawn from the music itself. Someone else, looking up, would see another sky.

Beneath the chart, each étude is written out as a handscroll. Its twelve rows are the circle of fifths laid flat, and time runs from left to right, as in a piano roll. Every note is a stroke of watercolour in the colour of its pitch on the wheel, pressed where the key is struck and thinning as the string dies away. The scroll unrolls with the music, so each stroke appears as its note sounds; what is still to come shows faintly, like the underdrawing in a copybook. A key reads as a band of neighbouring rows, and a change of key as that band moving. The paper is laid by the true solar time at which you arrive, so no two visits are painted quite alike.

“Nature always wears the colors of the spirit.”

Ralph Waldo Emerson, Nature (1836), chapter I

Emerson opens that chapter by asking his reader to look at the stars, and closes it by noticing that the same landscape can look different to the same person from one day to the next.

“I look at things through myself, and so all things wear my colours.”

Wang Guowei, Renjian cihua (1908)

Reading the sky

Position angle: The key on the circle of fifths: C at 0°, each fifth 30° clockwise.
Ring: Major keys on the outer ring; each relative minor on the inner ring, at the same angle.
Magnitude: The loudness of the recording on Pogson’s scale, one magnitude to 4 dB. Brighter stars are drawn larger.
Multiple stars: Études in the same key, drawn as one system: a triple in A minor and seven doubles.
Handscroll: A chromagram: time across, from the first note to the last; pitch class down, in the order of the circle of fifths, C at the top. Each stroke is a note, as broad as it was struck and fading as it decays. Touch the scroll to move to that moment.
Asterisms: Op. 10, solid, and Op. 25, dashed, each joined in order of publication. Op. 10 is built mostly from pairs in relative keys; Op. 25 moves more often by a third.

Credits

Music: Frédéric Chopin, 12 Études Op. 10 (1833) and 12 Études Op. 25 (1837).
Recordings: Edward Neeman, piano, recorded for Musopen’s Set Chopin Free (2014). Public domain; loudness-matched.
Method: A chromagram for pitch class, spectral flux for onsets, gated loudness for magnitude.
Curator: Theodore Ouyang