Definition
A comet is a single large star, pressed or rolled, fired from a tube, that leaves a long trail of sparks behind it throughout its climb, like the celestial body. Depending on composition the tail is gold (charcoal), silver (titanium, magnalium), glittering or coloured. Comets are fired as single shots of 30 to 100 mm, in candles, cakes and fans; they climb 30 to 120 m and last two to five seconds. A comet may end with a crossette split, a crackle or a small peony. It is used to draw lines, crossings and waves when fired at an angle; it is also the rising tail fixed to a shell to make its trajectory visible before the break.
In practice, for the display company
The comet is the pyrotechnician's drawing tool: it is what you angle to trace Vs, Xs and waves, one cue per tube. PyroDesk records the angle of each single shot in the firing plan, and PyroSimulator traces the angled trajectories with their trails, so you can compose the picture over the site plan and check the fallout.