translating spectra into a laser projection
It is quite at hand to use the graphical medium of a laser to translate spectra into a projection. Reminiscent of an oscilloscope and early vector based computer graphics , the laser was used to translate the spectral coordinates into the wave pattern. This was achieved by a python-based interface developed by Benjamin Staude, that computes the laser coordinates from the spectra and directly sends them to the laser projector, thereby avoiding the use of intricate commercial laser software.
A great challenge was the projection on the sphere of the Hayden Planetarium at the Museum of Natural History in New York City. Benjamin Staude developed a mathematical 3d model of the sphere and the two lasers, including their positions, focussing points and image planes. A graphical user interface allows the interactive control of the geometry and other parameters (as intensity of lasers, animation speed, ...). Above all the geo-corrections that compose one consistent animation with two laser projectors from different positions and angles can be adjusted interactively.
All software was written in Python using the numpy package. It was developed for the Easylase II USB card which provides an open API, and runs on Windows systems.
"The planetarium is turning"
In general the software gave as much freedom as possible to translate the spectra artistically. Not only the general appearance as the shapes of the curves could be defined, but also individual aspects as the painterly character of the animation's starting point could be designed. Finally the laser presentations interacted in their own way with the specific architectures, to be the interplay with the baroque facade in Venice or the reflections by the corrugated steel facade in Baltimore. In New York City the projections on the dome of the Hayden Planetarium at the Museum of Natural History was realized according to a reversed Mercator projection. With two lasers an area of almost 180 degreea on the upper part of the sphere was covered. A passenger watching the installation through the trees from Columbus Ave formulated the resulting astronishing effect: "Look, the planetarium it turning!"
Special thanks for their advice and help to: