Evans & Sutherland Digistar 1

The original Digistar and Digistar II were operated from a physical control panel roughly 3 by 4 feet in size, containing a keyboard, a six-degree-of-freedom joystick, and a large array of back-lit buttons. The operator performed the show with the body — steering the viewpoint through space with the joystick, punching illuminated buttons to summon models and celestial events. It is closer to a theatre organ or an aircraft cockpit than to a graphical user interface, a rare example of a public performance computer driven entirely by physical controls.

Among the back-lit buttons on the Digistar panel was one, used to move the viewpoint forward through space, labelled "Boldly Go" — after Star Trek's "where no man has gone before." The joke was earned. A Digistar laboratory prototype generated the star fields and tactical displays for Star Trek II: The Wrath of Khan (1982), filmed directly from the Digistar display; the film's opening 3.5-minute starfield fly-through became the first entirely computer-generated feature film sequence, and the Digistar team is credited in the film.

The Digistar projector is a calligraphic display: instead of scanning a raster, its single CRT drives the beam straight to each coordinate in a display list. Because a star's phosphor spot glows longer the more often it is hit, short display lists produce very bright stars — far brighter than a raster could — and darker blacks, because the empty sky is never struck. The result is a bright phosphorescent green sky that many visitors and planetarians report they cannot distinguish from white, and a star image free of the blocky artifacts of raster graphics.

Digistar 1 and 2 could only project dots and lines, so only wireframe models were possible; the system compensated by defocusing models to blur lines into surfaces (the Milky Way was a circle of parallel lines, defocused into a band). Focus across a dome from a single lens was imperfect, and the CRT lost brightness after roughly a thousand hours and needed replacement every year or so. Later versions replaced the physical console with an ordinary graphical user interface — the museum-relevant loss is precisely that embodied console. Digistar 3 (2002) finally brought full-dome raster video.