What is an Astronomical Clock?

Answer 1

An astronomical clock is a clock with special mechanisms and dials to display astronomical information, such as the relative positions of the sun, moon, zodiacal constellations, and sometimes major planets.

The term is loosely used to refer to any clock that shows, in addition to the time of day, astronomical information. This could include the location of the sun and moon in the sky, the age and phase of the moon, the position of the sun on the ecliptic and the current zodiac sign, the sidereal time, and other astronomical data such as the moon's nodes (for indicating eclipses) or a rotating star map.

Astronomical clocks usually represent the solar system using the geocentric model. The center of the dial is often marked with a disc or sphere representing the earth, located at the center of the solar system. The sun is often represented by a golden sphere, shown rotating around the earth once a day around a 24 hour analog dial. This view accords both with daily experience and with the philosophical world view of pre-Copernican Europe.

- From http://en.wikipedia.org/wiki/Astronomical_clock

Answer 2

Definition
The term is loosely used to refer to any clock that shows, in addition to the time of day, astronomical information. This could include the location of the sun and moon in the sky, the age and phase of the moon, the position of the sun on the ecliptic and the current zodiac sign, the sidereal time, and other astronomical data such as the moon's nodes (for indicating eclipses) or a rotating star map.

Astronomical clocks usually represent the solar system using the geocentric model. The center of the dial is often marked with a disc or sphere representing the earth, located at the center of the solar system. The sun is often represented by a golden sphere, shown rotating around the earth once a day around a 24 hour analog dial. This view accords both with daily experience and with the philosophical world view of pre-Copernican Europe.

Answer 3

The Atomic Clock in USA based on the half-life of radioactive elements

Answer 4

Master Clockmakers built a number of mechanical figures during the Middle Ages. One of the oldest and best known examples is the 700hundred-year-old Astronomical Clock in Prague. When the clock tower chimes the hour, a skeleton holding an hourglass rings a bell, and a Turk draws his sword. A door in the clocktower opens to reveal a series of animated figures that move across the top of the clock.

The astronomical clock was so amazing that people thought it was a magical device. After the it was built, the burghers decided to reward the clockmaker by putting-out his eyes. The townspeople were so proud of their magic clock that they made sure that the clockmaker would never build another one like it. When the clock broke-down a few years later, no one knew how to fix it. The Astronomical clock remained silent for next 300 years.

Later, clockmakers in Germany constructed many similar clocks -although none were as impressive as the one in Prague. Precision clockwork was also used to construct machines and mechanical toys.

In the 16'th Century, European trade with the Far East, and translations of Hero of Alexandria's writings from the 1'st Century, spurned new interest in constructing automatons. Automatons became quite fashionable among the wealthy.

Magician Boxes were a popular toy for wealthy adults. A disc with a question written on it is inserted into the device, and the figure of a magician points his wand at the answer.

In 1578, in a Latin treatise of mechanical instruments, Jacques Besson described the workings of a device which dispersed water, wine and oil through a single spigot.

In 1606, Henry Winstanley designed a similar device called "The Wonderful Barrel" which served hot and cold drinks "without mixture". Winstanley exhibited the Wonderful Barrel at his water theater on Picadilly, along with perpetual fountains, and other devices.

A rival engineer named Charles Butchered installed a New Mechanical Fountain at the Black Horse Inn in 1708 "which at command runs at one **** hot and cold liquor." The fountain also served tea, coffee, chocolate, sherry, white wine, cherry brandy and punch.



In the 18'th Century, mechanical pictures (tableux mecaniques) were quite popular. A framed painted landscape would spring-to-life by clockwork.

Mechanical theaters soon sprang-up. The biggest was the one at the gardens of Hellbrun near Salzburg, Austria. It contained over 113 hydraulically operated figures.

In 1722, Isaac Fawkes, a stage magician, displayed a musical clock as part of his act. The clock "played a variety of tunes on the organ, flute and flangolet with birds whistling and singing." At the Bartholomew Fair, Fawkes gave top billing to a device called the "Temple of the Arts." Mechanical musicians played while mechanized ships and ducks crossed a painted bay that was supposed to represent Gibralter. The ships were later replaced with a mechanical version of King George's coronation. And in honor of the Algerian Ambassador, a "moving picture" depicted an Algerian scene in which an apple tree blossomed and bore fruit.

Many supposedly mechanical devices were actually operated by live assistants using strings and pulleys. These included Balducci's automated drugstore, and "Blackmoore" -which chimed the number of pips on a playing card.

The most famous automaton of all -the automatic Turkish chessplayer, or "Psycho"- was actually a clever fraud. In 1769, the Baron Wolfgang Von Kempelen (who served as counselor on mechanics to the Empress Maria Theresa) was watching a performance at a party which made use of magnetic toys. The Baron bragged that he could build a much more thought-provoking diversion. The Empress told him he should go ahead and build one. The Baron worked on his invention for the next six months before presenting it in court. It was an automaton chess player dressed in traditional Turkish costume.

This incredible "thinking machine" fooled all the greatest minds of Europe. Learned men and courtiers came from far-and-wide to see it.



The Turk was seated behind a cabinet full of mechanical gears. The front of the cabinet opened-up to reveal the inner workings. When the machine was wound-up, the android came to life. It would turn its head from side-to-side, pick up chess pieces with slow, jerking movements, and move them to another position on the board. In this way, the android was able to play a game of chess against a real human opponent.

The courtiers were delighted, and the Baron von Kempelen became famous.

In reality, the chessplayer's gears were all fake; they were merely meant for show. A small person or child hid within the cabinet beneath the Turk. The cabinet was divided into four or five separate compartments. As the Baron opened the doors on the front of the machine to "prove" to the audience that there wasn't a person inside, the child would twist and contort to hide himself in a different part of the box (one of which was actually a drawer underneath the main compartment!) When the chessplayer was wound-up, the person inside the box would crawl up into the body of the Turk, and move the head and arms just like a puppet. The "machine" would magically spring-to-life, and begin to play a game of chess.

The Turk may have been a fake, but Jacques de Vaucanson's creations were purely mechanical. In 1738, he designed an automaton flute player "that many learned men thought was human."