A norns script inspired by John Cage's Atlas Eclipticalis (1961–62), in which Cage overlaid transparent staff paper onto astronomical star charts: stars became note heads, vertical position determined pitch, horizontal position rhythm. Every performance is unrepeatable.
This script renders a star field as a live musical score. A cursor sweeps through the sky and plays each star it crosses as a note — pitch mapped to vertical position across five staff lines, amplitude to stellar magnitude. Set a date and location in the params menu; the sky shown is astronomically accurate for that moment and place.
Startup screen — twinkling Orion constellation
Playing screen — scan mode, star at cursor just triggered (flash ring visible). Staff lines, constellation lines, and HUD showing date / sidereal time / coordinates.
;install https://github.com/robinmeier/atlas-eclipticalis
Or clone into ~/dust/code/atlas-eclipticalis/.
| Control | Action |
|---|---|
| E1 | Zoom in / out (centered on screen) |
| K1 hold + E1 | Star density — percentage of stars visible |
| E2 (cursor mode) | Pan through the sky manually; stars crossing the line play |
| E2 (scan mode) | Scan speed — clockwise: faster, counter-clockwise: slower → stop → reverse |
| E3 | Vertical pan (adjusts displayed latitude) |
| K2 | Toggle cursor ↔ scan mode (switching to cursor resets speed to zero) |
Press any key on the startup screen to dismiss it.
Cursor mode — the cursor sits fixed at the centre of the screen. Rotate E2 to pan the sky past it; each star that crosses plays a note. Reversing direction replays stars.
Scan mode — the cursor stays at centre and the sky glides past automatically at the speed set by E2. Stars trigger as they cross. Reversing the speed rewinds through the score.
| Position | Display |
|---|---|
| Top-left | Date |
| Top-right | Sidereal time — advances or rewinds with E2 (100 virtual pixels = 1 hour) |
| Bottom | Latitude (from vertical scroll), longitude (from params), star density % |
The cursor line is dim in cursor mode and bright in scan mode.
Constellation lines are visible at zoom ≤ 1.5×. Seven constellations are drawn: Orion, Ursa Major, Cassiopeia, Scorpius, Leo, Cygnus, and Crux.
| Parameter | Range | Description |
|---|---|---|
| Year / Month / Day / Hour | — | Starting date and sidereal time |
| Latitude | −90 – 90 | Observer latitude (default 48°N — Paris) |
| Longitude | −180 – 180 | Observer longitude (default 2°E) |
| Pitch Base | 24 – 84 MIDI | Note at bottom of staff |
| Pitch Range | 1 – 48 semi | Semitone span from bottom to top of staff |
| Volume | 0 – 1 | Audio output level |
| Output | audio / midi / audio+midi | Signal routing |
| MIDI Device | vport list | Output MIDI port |
| MIDI Channel | 1 – 16 | Output channel |
John Cage's original Atlas Eclipticalis was composed for any number of instruments from 1 to 86. Working in 1961–62, Cage selected pages from the Atlas Borealis star atlas and overlaid transparent staff paper to derive 86 independent parts. The score specifies no duration, no required instruments, and no fixed order — every realisation is a unique encounter between the performers, the time, and the stars.
This script takes that spirit into a live, interactive medium: the sky you see is real, the music it makes is yours.