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ANNOUNCEMENTS:

This announcement provides information about the return of midterm exams, the suspension of homework for the week, and the extension of the observing project due date. It also includes details about the Eratosthenes observing project help session and Fiske Field access. Additionally, it mentions the availability of the public Fiske show for extra credit and provides information on eclipse numerology, eclipse intervals, tracking eclipses using written records, longer eclipse cycles, and the Saros cycle.

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ANNOUNCEMENTS:

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  1. ANNOUNCEMENTS: • MIDTERM EXAMS WILL BE RETURNED AT THE END OF THE CLASS PERIOD NEXT TUESDAY • NO HOMEWORK THIS WEEK. HWs WILL RECOMMENCE NEXT WEEK • FIRST OBSERVING PROJECT DUE DATE IS EXTENDED TO THURSDAY OCTOBER 27thWHEN 2 (TWO) OBSERVING PROJECTS ARE DUE. • ERATOSTHENES OBSERVING PROJECT HELP SESSION (AND FOLSOM FIELD ACCESS: NEXT TUESDAY 3:30-5pm gate 5 Folsom Field

  2. PUBLIC FISKE SHOW CAN BE USED FOR EXTRA CREDIT. FREE TO CU STUDENTS ON THURSDAY. • (WRITE UP 1--2 PAGES ON WHAT YOU LEARNED)

  3. ECLIPSE NUMEROLOGY: • ECLIPSE “SEASONS” (separated by ½ Draconic period of Sun)= 173 DAYS). ECLIPSES ARE POSSIBLE TO happen twice per year when Full and/or New Moon occurs in or near the Lunar Nodes. More solar than lunar eclipses globally (Earth is bigger target for a shadow than the Moon) • CAN BE TRACKED USING LUNAR STANDSTILLS ! 2. But eclipses do NOT happen on a 173 day interval because all eclipses have to happen at NEW (Solar eclipse) or Full MOON (Lunar eclipse).  ECLIPSE INTERVALS: 148 days (5 “Moonths”), 163 days (5½ “Moonths”) or 177/178 days (6 “Moonths”). • CAN BE TRACKED USING WRITTEN RECORDS… e.g., DRESDEN CODEX OF THE MAYA • LONGER ECLIPSE CYCLES. The pattern of eclipse intervals repeats exactly over a much longer period (e.g., ~ 33 years in Dresden Codex). Eclipses separated by these longer eclipse periods are closely related; i.e., similar types of eclipses (total… total, annular ..annular)

  4. MAYA ECLIPSE TABLE IN THE DRESDEN CODEX SHORT ECLIPSE SERIES IN BETWEEN “SKIPS” (NO ECLIPSE)

  5. Longer Eclipse Cycles(EVEN NUMBERS OF SYNODIC & DRACONIC MONTHS ) Chinese cycle SAROS CYCLE MAYA CYCLE = 46 TSOLKIN ROUNDS

  6. THE SAROS: AN AMAZING BABYLONIAN-DISCOVERED ECLIPSE PREDICTOR…STILL USED TODAY FOR ECLIPSES! Some Eclipses of Saros Series #136 Number Date Type Duration* Comments 1 1360 June 14 Partial [5%] 8 1486 Aug 29 Partial [99%] Last Partial 9 1504 Sept 8 Annular 31 seconds 15 1612 Nov 12 Hybrid 1 sec 21 1721 Jan 27 Total 1 min 7 secs First Total 31 1901 May 18 Total 6 min 29 secs 32 1919 May 29 Total 6 min 51 secs “Eddington’s Eclipse” 33 1937 Jun 8 Total 7 min 4 secs 34 1955 Jun 20 Total 7 min 8 secs Longest Total 35 1973 Jun 30 Total 7 min 4 secs 36 1991 July 11 Total 6 min 53 secs “Yelapa eclipse” 37 2009 July 22 Total 6 min 39 secs 38 2027 Aug 2 Total 6 min 23 secs 39 2045 Aug 12 Total 6 min 6 secs 40 2063 Aug 24 Total 5 min 49 secs 41 2081 Sept 3 Total 5 min 33 secs 42 2099 Sept 14 Total 5 min 18 secs 64 2496 May 13 Total 1 min 2 secs Last Total 65 2514 May 25 Partial [95%] First Partial 71 2622 July 30 Partial [10 ½ %] Last Partial * Duration of Totality in minutes and seconds. Where the eclipse is partial, instead of duration, the maximum percentage of the Sun eclipsed is given inside square brackets.

  7. More than a hundred years ago an extraordinary mechanism was found by sponge divers at the bottom of the sea near the tiny island of Antikythera, between Greece and Crete. It astonished the whole international community of experts on the ancient world. Was it an astrolabe? Was it an orrery or an astronomical clock? Or something else?

  8. A MODERN MODEL OF THE ANTIKYTHERA MECHANISM c. 200 BCE Go to Fiske show format

  9. The Antikythera Mechanism: dates from 200—100 BCE; discovered in 1900 by a team of sponge divers off the south coast of Greece (near the islet of Antikythera, midway between the Peloponnese and Crete) Speaking of its current location in Athens: “It looks like something from another world – nothing like the classical statues and vases that fill the rest of the echoing hall. Three flat pieces of what looks like green, flaky pastry are supported by plastic cradles. Within each fragment, layers of something that was once metal have been squashed together and are now covered in calcareous accretions and various corrosions, from the whitish tin oxide to the dark bluish green of copper chloride. This thing spent 2,000 years at the bottom of the sea before making it to the National Archaeological Museum in Athens, and it shows. “But it is the detail that takes my breath away. Beneath the powdery deposits, tiny cramped writing is visible along with a spiral scale; there are traces of gear-wheels edged with jagged teeth. Next to the fragments an X-ray shows some of the object’s internal workings. It looks just like the inside of a wristwatch. “The is the Antikythera Mechanism.” Nature magazine Vol 444, 30 November 2006

  10. Oct 13 Lecture .ppt ended here but below is included for those who missed the Fiske presentation Nature video: http://www.nature.com/nature/videoarchive/antikythera/

  11. New analysis by Tony Freeth (U Cardiff, Wales) and collaborators used surface imaging and high resolution X-ray tomography to determine that the Antikythera Mechanism had at least 30 bronze gears, all with triangular teeth ranging in number from 15 to 223. The purposes of these gears includes: • Day in lunar month and Solar Year • Exact location of the Moon including the ellipticity of its orbit as originally described by Hipparchos of Rhodes in c. 150 BCE • Day number in the 76 year Callippic cycle (4 times the Year of Meton, upon which the Jewish luni-solar calendar is based). Over this period the Moon returns to the same phase on the same day of the year (This luni-solar calendar was used throughout the eastern Mediterranean including Greece and Sicily) • Day in the Saros Cycle, the primary eclipse cycle of the Babylonians in which 223 synodic periods (lunar phase cycles) is the same as 242 draconic months (time period for Moon to return to the same node in its orbit). Because this period is 18.03 years Saros eclipses also repeat at the same time of year. • Suggestions of gears now lost that determined accurate planetary positions. >> See Nature Magazine Volume 444/30 November 2006

  12. INSTRUCTION MANUAL engraved on inside mechanism’s “back door” HIGHLIGHTED PORTIONS OF TEXT : At left: “76 years, 19 years” for Calippic and Metonic calendar cycles. At right: “223” for the Saros cycle and “on the spiral subdivisions 235” confirming the calendrical use of one of the two back dials.

  13. EXAMPLES OF ECLIPSE DETAILS ON BACK SIDE OF MECHANISM • 18 sets of “GLYPHS” which were inscribed within some of the 223 divisions of the spiral dial. Each "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 for Solar Eclipses, or sunset for Lunar Eclipses) is given. • 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.

  14. ANNULAR ECLIPSE of MAY 2012 is a member of SAROS ECLIPSE SERIES #128 WHICH STARTED WITH A PARTIAL ECLIPSE ON NOV 16, 1705 AND WILL CONCLUDE WITH A PARTIAL ECLIPSE ON NOV 1st 2282.

  15. What Richard Feynmann (Nobel Laureate in Physics) had to say about the Antikythera Mechanism Yesterday morning I went to the archeological museum. . . . Also, it was slightly boring because we have seen so much of that stuff before. Except for one thing: among all those art objects there was one thing so entirely different and strange that it is nearly impossible. It was recovered from the sea in 1900 and is some kind of machine with gear trains, very much like the inside of a modern wind-up alarm clock. The teeth are very regular and many wheels are fitted closely together. There are graduated circles and Greek inscriptions. I wonder if it is some kind of fake.

  16. New analysis by Tony Freeth, Mike Edmunds (U Cardiff, Wales) and collaborators used surface imaging and high resolution X-ray tomography to determine that the Antikythera Mechanism had at least 30 bronze gears, all with triangular teeth ranging in number from 15 to 223. The purposes of these gears includes: • Day in lunar month and Solar Year • Exact location of the Moon AND Sun including the ellipticityof its orbit as originally described by Hipparchos of Rhodes in c. 150 BCE • Day number in the 76 year Callipic cycle (4 times the Year of Meton, upon which the Jewish luni-solar calendar is based). Over this period the Moon returns to the same phase on the same day of the year • Day in the Saros Cycle, the primary eclipse cycle of the Babylonians in which 223 synodic periods (lunar phase cycles) is the same as 242 draconic • Suggestions of gears now lost that determined accurate planetary positions. >> See Nature Magazine Volume 444/30 November 2006

  17. Prague Orloj 1410 CE Prague Czechoslovakia City Hall

  18. Padova Italy Town Clockcirca 1344 CE

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