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Astrarium Of Giovanni Dondi Dell'Orologio
The Astrarium of Giovanni Dondi dell'Orologio was a complex astronomical clock built between 1348 and 1364 in Padova, Italy, by the doctor and clock-maker Giovanni Dondi dell'Orologio. The Astrarium had seven faces and 107 moving parts; it showed the positions of the sun, the moon and the five planets then known, as well as religious feast days. It was one of the first mechanical clocks to be built in Europe. The ''Tractatus astrarii'' Dondi documented the Astrarium in detail in the ''Tractatus astrarii'', which is the earliest complete surviving description of its kind; the St Albans abbey clock designed by Richard of Wallingford predates it, but survives only as fragments (reconstructed by John North). In the introduction, Dondi writes that his machine was built in accordance with the 13th-century ''Theorica planetarum'' of Campano di Novara, and to demonstrate the validity of the descriptions of the motion of heavenly bodies of Aristotle and Avicenna. The ''Tractatus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giovanni Di Dondi Clock
Giovanni may refer to: * Giovanni (name), an Italian male given name and surname * Giovanni (meteorology), a Web interface for users to analyze NASA's gridded data * ''Don Giovanni'', a 1787 opera by Wolfgang Amadeus Mozart, based on the legend of Don Juan * Giovanni (Pokémon), boss of Team Rocket in the fictional world of Pokémon * Giovanni (World of Darkness), a group of vampires in ''Vampire: The Masquerade/World of Darkness'' roleplay and video game * "Giovanni", a song by Band-Maid from the 2021 album ''Unseen World'' * ''Giovanni's Island'', a 2014 Japanese anime drama film * ''Giovanni's Room'', a 1956 novel by James Baldwin * Via Giovanni, places in Rome See also * * *Geovani *Giovanni Battista *San Giovanni (other) San Giovanni, the Italian form of "Saint John", is a name that may refer to dozens of saints. It may also refer to several places (most of them in Italy) and religious buildings: Places France *San-Giovanni-di-Moriani, a municipality of the Hau . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primum Mobile
In classical, medieval, and Renaissance astronomy, the Primum Mobile (Latin: "first movable") was the outermost moving sphere in the geocentric model of the universe. The concept was introduced by Ptolemy to account for the apparent daily motion of the heavens around the Earth, producing the east-to-west rising and setting of the sun and stars, and reached Western Europe via Avicenna. Appearance and rotation The Ptolemaic system presented a view of the universe in which apparent motion was taken for real – a viewpoint still maintained in common speech through such everyday terms as ''moonrise'' and ''sunset''. Rotation of the Earth on its polar axis – as seen in a heliocentric solar system, which (while anticipated by Aristarchus) was not to be widely accepted until well after Copernicus – leads to what earlier astronomers saw as the real movement of all the heavenly bodies around the Earth every 24 hours. Astronomers believed that the seven naked-eye planets (including ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duchy Of Milan
The Duchy of Milan ( it, Ducato di Milano; lmo, Ducaa de Milan) was a state in northern Italy, created in 1395 by Gian Galeazzo Visconti, then the lord of Milan, and a member of the important Visconti family, which had been ruling the city since 1277. At that time, it included twenty-six towns and the wide rural area of the middle Padan Plain east of the hills of Montferrat. During much of its existence, it was wedged between Savoy to the west, Venice to the east, the Swiss Confederacy to the north, and separated from the Mediterranean by Genoa to the south. The duchy was at its largest at the beginning of the 15th century, at which time it included almost all of what is now Lombardy and parts of what are now Piedmont, Veneto, Tuscany and Emilia-Romagna. Under the House of Sforza, Milan experienced a period of great prosperity with the introduction of the silk industry, becoming one of the wealthiest states during the Renaissance. From the late 15th century, the Duchy of M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gian Galeazzo Visconti
Gian Galeazzo Visconti (16 October 1351 – 3 September 1402), was the first duke of Milan (1395) and ruled the late-medieval city just before the dawn of the Renaissance. He also ruled Lombardy jointly with his uncle Bernabò. He was the founding patron of the Certosa di Pavia, completing the Visconti Castle at Pavia begun by his father and furthering work on the Duomo of Milan. He captured a large territory of Northern Italy and the Po valley. He threatened war with France in relation to the transfer of Genoa to French control as well as issues with his beloved daughter Valentina. When he died of fever in the castello of Melegnano, his children fought with each other and fragmented the territories that he had ruled. Biography During his patronage of the Visconti Castle, he contributed to the growth of the collection of scientific treatises and richly illuminated manuscripts in the Visconti Library. Gian Galeazzo was the son of Galeazzo II Visconti and Bianca of Savoy. His fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leap Year
A leap year (also known as an intercalary year or bissextile year) is a calendar year that contains an additional day (or, in the case of a lunisolar calendar, a month) added to keep the calendar year synchronized with the astronomical year or seasonal year. Because astronomical events and seasons do not repeat in a whole number of days, calendars that have a constant number of days in each year will unavoidably drift over time with respect to the event that the year is supposed to track, such as seasons. By inserting (called '' intercalating'' in technical terminology) an additional day or month into some years, the drift between a civilization's dating system and the physical properties of the Solar System can be corrected. A year that is not a leap year is a common year. For example, in the Gregorian calendar, each leap year has 366 days instead of 365, by extending February to 29 days rather than the common 28. These extra days occur in each year that is an integer multipl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitreous Enamel
Vitreous enamel, also called porcelain enamel, is a material made by fusing powdered glass to a substrate by firing, usually between . The powder melts, flows, and then hardens to a smooth, durable vitreous coating. The word comes from the Latin , meaning "glass". Enamel can be used on metal, glass, ceramics, stone, or any material that will withstand the fusing temperature. In technical terms fired enamelware is an integrated layered composite of glass and another material (or more glass). The term "enamel" is most often restricted to work on metal, which is the subject of this article. Essentially the same technique used with other bases is known by different terms: on glass as ''enamelled glass'', or "painted glass", and on pottery it is called ''overglaze decoration'', "overglaze enamels" or "enamelling". The craft is called "enamelling", the artists "enamellers" and the objects produced can be called "enamels". Enamelling is an old and widely adopted technology, for mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominical Letter
Dominical letters or Sunday letters are a method used to determine the day of the week for particular dates. When using this method, each year is assigned a letter (or pair of letters for leap years) depending on which day of the week the year starts. Dominical letters are derived from the Roman practice of marking the repeating sequence of eight letters A–H (commencing with A on 1 January) on stone calendars to indicate each day's position in the eight-day market week (''nundinae''). The word is derived from the number nine due to their practice of inclusive counting. After the introduction of Christianity a similar sequence of seven letters A–G was added alongside, again commencing with 1 January. The dominical letter marks the Sundays. Nowadays they are used primarily as part of the computus, which is the method of calculating the date of Easter. A common year is assigned a single dominical letter, indicating which lettered days are Sundays in that particular year (hence th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daylight
Daylight is the combination of all direct and indirect sunlight during the daytime. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by Earth and terrestrial objects, like landforms and buildings. Sunlight scattered or reflected by astronomical objects is generally not considered daylight. Therefore, daylight excludes moonlight, despite it being reflected indirect sunlight. Definition Daylight is present at a particular location, to some degree, whenever the Sun is above the local horizon. (This is true for slightly more than 50% of the Earth at any given time. For an explanation of why it is not exactly half, see here). However, the outdoor illuminance can vary from 120,000 lux for direct sunlight at noon, which may cause eye pain, to less than 5 lux for thick storm clouds with the Sun at the horizon (even <1 lux for the most extreme case), which may make shadows from distant [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Movable Feast
A moveable feast is an observance in a Christian liturgical calendar which occurs on different dates in different years.John Ayto ''Oxford Dictionary of English Idioms'' 2010 p123 019954378X "a movable feast an event which takes place at no regular time. In a religious context a movable feast is a feast day (especially Easter Day and the other Christian holy days whose dates are related to it) which does not occur on the same calendar date each year." Spring paschal feasts Often considered the most important Christian observance, Spring paschal feasts are a fixed number of days before or after Easter Sunday, which varies by 35 days since it depends partly on the phase of the moon and must be computed each year. In the Hebrew calendar, the new moon of Aviv, spring, is fixed as the Lunar New Year, and the month is called Nisan. The 14 of Nisan is the paschal full moon, the day of the Pesach seder,_a_ritual_meal_ telling_the_story_of_telling_the_story_of_the_Exodus">Haggadah.ht ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julian Calendar
The Julian calendar, proposed by Roman consul Julius Caesar in 46 BC, was a reform of the Roman calendar. It took effect on , by edict. It was designed with the aid of Greek mathematicians and astronomers such as Sosigenes of Alexandria. The calendar became the predominant calendar in the Roman Empire and subsequently most of the Western world for more than 1,600 years until 1582, when Pope Gregory XIII promulgated a minor modification to reduce the average length of the year from 365.25 days to 365.2425 days and thus corrected the Julian calendar's drift against the solar year. Worldwide adoption of this revised calendar, which became known as the Gregorian calendar, took place over the subsequent centuries, first in Catholic countries and subsequently in Protestant countries of the Western Christian world. The Julian calendar is still used in parts of the Eastern Orthodox Church and in parts of Oriental Orthodoxy as well as by the Berbers. The Julian calenda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balance Wheel
A balance wheel, or balance, is the timekeeping device used in mechanical watches and small clocks, analogous to the pendulum in a pendulum clock. It is a weighted wheel that rotates back and forth, being returned toward its center position by a spiral torsion spring, known as the balance spring or ''hairspring''. It is driven by the escapement, which transforms the rotating motion of the watch gear train into impulses delivered to the balance wheel. Each swing of the wheel (called a "tick" or "beat") allows the gear train to advance a set amount, moving the hands forward. The balance wheel and hairspring together form a harmonic oscillator, which due to resonance oscillates preferentially at a certain rate, its resonant frequency or "beat", and resists oscillating at other rates. The combination of the mass of the balance wheel and the elasticity of the spring keep the time between each oscillation or "tick" very constant, accounting for its nearly universal use as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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