saltbleachedbones:garbagealien:Astronomical CompendiaOk we need to talk about this. I just now found
saltbleachedbones:garbagealien:Astronomical CompendiaOk we need to talk about this. I just now found out about these things and they are literally the coolest things I’ve ever seen in my entire life.An astronomical compendium (plural = compendia) is an instrument that carry numerous devices for telling the time and performing astronomical calculations. Many compendia were made in the German lands in the late 16th and early 17th centuries. They are often beautifully engraved in gilt brass. Typically such compendia carry a sundial, various lunar and solar volvelles, a compass, tables of latitude, and a perpetual calendar. Two characteristics are typical of the construction of these instruments: first, they were often made as lavishly as possible; second, they are ingeniously constructed, with as many instruments as possible filling the available space. Most of the instruments on a compendium are used to simplify astronomical calculations. Many compendia have volvelles - rotating discs that show the phases of the Moon, the positions of planets, and other such phenomena.Some compendia also carry stereographic projections. These are multi-purpose maps of the heavens, allowing many astronomical calculations to be simplified. Using these, people could determine the time of sunrise and sunset, and the position of the Sun in its annual (apparent) motion through the sky.source -- source link
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