The first recorded use of the heliograph was in 405 BC, when the Ancient Greeks used polished shields to signal in battle. In about 35 AD, the Roman emperor Tiberius, by then very unpopular, ruled his vast empire from a villa on the Isle of Capri. It is thought that he sent coded orders daily by heliograph to the mainland, eight miles away. The first to think of mounting mirror systems onto airships is not recorded, but the refinements made by Baron Klaus Wulfenbach have brought heliography to a new level of accomplishment and efficiency.
The Wulfenbach airships used by the Heliolux Air Fleet are among the swiftest in the fleet overall; they are relatively small with oversized engines and light-weight construction in the gondola and fittings. Each has a set of three mirrors mounted dorsally, controlled with precision motors from inside the gondola, although manually cranking adjustments can be done in an emergency. The array allows message repeats to be sent in three directions simultaneously. Flash breaks are created by quick re-angling of the mirror. The mirrors themselves have been carefully shaped to create the tightest-possible focus of the reflected sunlight.
The ships communicate among themselves by using preset positions — an attention signal will be directed towards a predicted position at various precise altitudes until the next ship in the chain responds. Messages have been passed around storm fronts by repeating above the cloud deck and then down to the next normally-positioned ship. Observers in the gondola are on constant watch for emergency attention message flashes; regular traffic is passed at scheduled times.
It Gilgamesh Wulfenbach extrapolated the Baron's order for the Fleet to sail en masse to Mechanicsburg so that their equipment could focus multiple intense beams at specific targets. The combined energy thus focused would be the equivalent of a very large death ray, and from entirely flexible and hard-to-reach positions (except the reasoning from either Wulfenbach didn't account for the functional status of the Torchmen).that the Heliolux equipment could also be used as weaponry.
As one can see from the picture, the crewmen operating the external mirror rigs wear light-absorbing facepaint marks below their eyes.