archive-gr.com » GR » A » ANTIKYTHERA-MECHANISM.GR

Total: 953

Choose link from "Titles, links and description words view":

Or switch to "Titles and links view".
  • Were there others? | The Antikythera Mechanism Research Project
    suggest that the manufacturer modified his design as he built the mechanism This leads to the conclusion that he must have built a number of predecessors However we don t know if he was the first in a tradition of makers or the last It has been suggested that the number of such mechanisms may have numbered in 10 s and at least some of these should demonstrate an evolution

    Original URL path: http://www.antikythera-mechanism.gr/faq/general-questions/were-there-others (2016-02-11)
    Open archived version from archive


  • Why haven't we found any others? | The Antikythera Mechanism Research Project
    recyclable commodity Don t forget bronze was used for low domination coinage at the time of the Mechanism Consequently bronze finds from antiquity are remarkably rare In fact many of the significant historical bronze finds have been made underwater where they were inaccessible to those who might have reworked them Bookmark Search this post with Google Plus One Pinterest Login or register to post comments Tags General questions Rate This

    Original URL path: http://www.antikythera-mechanism.gr/faq/general-questions/found-any-others (2016-02-11)
    Open archived version from archive

  • How many gears does it have? | The Antikythera Mechanism Research Project
    gears are not sufficient for the mechanism to fulfil its known functions and a further 5 gears are required However this scheme leaves a lone unused gear in Fragment D This is probably part of the missing epicycle gearing that modeled Hipparchos s solar model and the planetary mechanisms The total number of gears in the Mechanism depends upon how many planets the mechanism modelled and how accurately their motions

    Original URL path: http://www.antikythera-mechanism.gr/faq/general-questions/how-many-gears (2016-02-11)
    Open archived version from archive

  • What was it for? | The Antikythera Mechanism Research Project
    proposed that one reason we know so little of these mechanisms is that they were bound by military or political secrecy Another common suggestion is that it could have been an aid to navigation especially as the ancient inhabitants of Rhodes were notorious for their navigational skills However this seems unlikely as it would be an impractical device to use at sea and seems excessive for the purposes of navigation It would have been a more useful tool to astronomers for assisting in making land based astronomical measurements Indeed with knowledge of eclipse timings it would assist in making measurements on a world scale for example longitude The first Mechanisms could have been built purely on the basis of seeing if it could be done Indeed researchers are still making models of the mechanism today to see if the theory can be put into practice Unfortunately this does not apply in the case of the Antikythera Mechanism as it is not thought to be the first of its kind A final possibility is that it could have been used as a teaching aid From the evidence of its construction it was designed to be taken apart easily This could be

    Original URL path: http://www.antikythera-mechanism.gr/faq/general-questions/what-was-it-for (2016-02-11)
    Open archived version from archive

  • What is a Parapegma? | The Antikythera Mechanism Research Project
    descriptions marking each day The peg could be advanced each day and on appropriate days the associated inscription would predict certain astronomical and meteorological events The second century AD Alexandrian astronomer Claudius Ptolemy included a such a calendar in his work known as Phaseis phases of fixed stars and collection of weather changes the core of which is a parapegma a list of dates of seasonally regular weather changes first appearances and last appearances of stars or constellations at sunrise or sunset and solar events such as solstices all organized according to the solar year Ptolemy believed that the astronomical phenomena caused the changes in seasonal weather his explanation of why there was not an exact correlation of these events was that the physical influences of other heavenly bodies also came into play Hence for him weather prediction was a special division of astrology Further reading 1 2 1 Astronomy Weather and Calendars in the ancient world Parapegmata and Related Texts in Classical and Near Eastern Societies Lehoux Daryn Cambridge p xiv 566 2007 2 Geminos s Introduction to the Phenomena A Translation and Study of a Hellenistic Survey of Astronomy Evans James and Berggren Lennart J p 346 2006

    Original URL path: http://www.antikythera-mechanism.gr/faq/astronomical-questions/what-is-a-parapegma (2016-02-11)
    Open archived version from archive

  • What are the Sidereal, Synodic, Tropical, Anomalistic and Draconic months? | The Antikythera Mechanism Research Project
    part of the Moon that is illuminated by the Sun from different angles as the Moon traverses its orbit So the appearance depends on the position of the Moon with respect to the Sun as seen from the Earth Because the Earth orbits the Sun it takes the Moon extra time after completing a sidereal month i e a full circle to catch up and return to the same position with respect to the Sun This longer period is called the synodic month Tropical Month It is customary to specify positions of celestial bodies with respect to the vernal equinox Because of precession this point moves back slowly along the ecliptic Therefore it takes the Moon less time to return to an ecliptic longitude of zero than to the same point amidst the fixed stars This slightly shorter period is known as tropical month The tropical month of the Moon is the analogous tropical year of the Sun Anomalistic Month Like all orbits the Moon s is an ellipse rather than a circle However the orientation as well as the shape of this orbit is not fixed In particular the position of the extreme points the line of the apsides perigee and apogee makes a full circle lunar precession in about nine years It takes the Moon longer to return to the same apsis because it moved ahead during one revolution This longer period is called the anomalistic month The apparent diameter of the Moon varies with this period and therefore this type of month has some relevance for the prediction of eclipses whose extent duration and appearance whether total or annular depend on the exact apparent diameter of the Moon Draconic or Draconitic Month The orbit of the Moon lies in a plane that is tilted with respect to

    Original URL path: http://www.antikythera-mechanism.gr/faq/astronomical-questions/what-are-the-different-months (2016-02-11)
    Open archived version from archive

  • What are the Saros and Exeligmos cycles? | The Antikythera Mechanism Research Project
    around the Earth is tilted with respect to the plane of the orbit of the Earth around the Sun the ecliptic An eclipse can only occur when the Moon is close to the plane of the orbit of the Earth The points at which the Moon s orbit crosses the ecliptic are known as nodes The period of time it takes for the Moon to to complete an orbit from one node to the same node is known as the Draconitic Month The Draconitic month is slightly shorter than the Synodic month The main reason for this is that during the time that the Moon has completed an orbit around the Earth the Earth and Moon have completed about 1 13th of their orbit around the Sun The Saros Cycle is the most well known and one of the best eclipse cycles It was discovered by ancient Babylonian astronomers several centuries BC and is based upon 223 synodic months equaling 242 draconitic months to within 51 min It is a period of about 6585⅓ days approximately 18 years 11⅓ day In the case of an eclipse of the Sun this ⅓ day means the region of visibility shifts west one third of the way around the world and most places from which the first eclipse was visible do not see any of the second one In the case of an eclipse of the Moon the next eclipse might still be visible from the same location as long as the Moon is above the horizon A more useful eclipse cycle is the triple Saros or Exeligmos Cycle which has the benefit that it has an almost integer number of days So the next eclipse will be visible from a location close to the first one in contrast to the Saros Bookmark

    Original URL path: http://www.antikythera-mechanism.gr/faq/astronomical-questions/saros-and-exeligmos-cycles (2016-02-11)
    Open archived version from archive

  • What are the Lower Back Dials "Glyphs"? | The Antikythera Mechanism Research Project
    of the lower back dial contain 16 sets of characters which were inscribed within some of the 223 divisions of the spiral dial Each set of characters or glyph consists of 4 to 10 characters Nearly all the glyphs contain S lunar eclipse from SELHNH Moon or H solar eclipse from HLIOS Sun Some glyphs contain both lunar and solar eclipse In each case the hour after sunrise or sunset is given Some glyphs have a pair of characters that may be interpreted as an abbreviation of day hemera possibly indicating that the predicted lunar eclipse was diurnal The last character s in each case provide an alphabetical index perhaps used cross reference the glyphs to some other text The lower back dial displayed the 223 synodic months of the Saros cycle with a subsidiary dial displaying the Triple Saros or Exeligmos cycle By using these dials in combination it would have been possible to use the mechanism to predict the time hour day month year of both lunar and solar eclipses Further reading 192 Bookmark Search this post with Google Plus One Pinterest Login or register to post comments Tags Astronomical questions Rate This Select rating Poor Fair Good

    Original URL path: http://www.antikythera-mechanism.gr/faq/astronomical-questions/what-are-the-glyphs (2016-02-11)
    Open archived version from archive



  •