This work analyzes the phase correlation of the three lunar cycles and the Saros/Exeligmos cycle, after the study of the chapter "About Exeligmos" in "Introduction to the Phenomena" by Geminus. The main result is that each Exeligmos/Saros... more
This work analyzes the phase correlation of the three lunar cycles and the Saros/Exeligmos cycle, after the study of the chapter "About Exeligmos" in "Introduction to the Phenomena" by Geminus. The main result is that each Exeligmos/Saros Cycle began on specific, rare dates directly related to a specific phase of the three lunar cycles. The Annular Solar eclipse on December 22 th 178BC belonging to Saros series 58, marks the start of the "Prominent Saros Cycle Apokatastasis", analyzed in this paper. After the analysis of the two Parapegma plates position on Antikythera Mechanism Front plate, the date of Winter Solstice/December 23 rd 178BC could be considered as the probable date of the start of the Mechanism Metonic dial. This date is directly correlated to the Exeligmos/Saros specific dates. During these two neighboring dates, the religious festival of Isia was celebrated in Egypt and the Hellenistic Greece. The correlation of these results, lead to the calculation of the initial calibration date/pointers position which is ideal, functional and representative for the specific design of the Antikythera Mechanism.
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The unplaced Fragment D of the Antikythera Mechanism with an unknown operation was a mystery since the beginning of its discovery. The gear-r1, which was detected on the Fragment radiographies by C. Karakalos, is preserved in excellent... more
The unplaced Fragment D of the Antikythera Mechanism with an unknown operation was a mystery since the beginning of its discovery. The gear-r1, which was detected on the Fragment radiographies by C. Karakalos, is preserved in excellent condition, but this was not enough to correlate it to the existing gear trainings of the Mechanism. The suggestion that this gear could be a part of the hypothetical planet indication gearing is still a hypothesis since no mechanical evidence has been preserved. After the analysis of AMRP tomographies of Fragment D and its mechanical characteristics revealed that it could be part of the Draconic gearing. Although the Draconic cycle was well known during the Mechanism’s era as represents the fourth Lunar cycle, it seems that it is missing from the Antikythera Mechanism. The study of Fragment D was supported by the bronze reconstruction of the Draconic gearing by the authors. The adaptation of the Draconic gearing on the Antikythera Mechanism improves its functionality and gives answers on several questions.
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Chemical reactions with seawater changed the bronze material and the color of the Antikythera Mechanism. The deformation and the displacement of the bronze parts are clearly evident on the visual photographs, on Antikythera Mechanism... more
Chemical reactions with seawater changed the bronze material and the color of the Antikythera Mechanism. The deformation and the displacement of the bronze parts are clearly evident on the visual photographs, on Antikythera Mechanism Research Project (AMRP) X-ray radiographs, and computed tomography (CT) scans as a result of the under-seawater material density change and the dehydration of the Mechanism after its removal from the Aegean/Kretan Sea bottom. In present work the first steps of the copper/bronze corrosion under the sea are simulated and presented. The geometric changes and the deformations of the Mechanism parts, which have repercussions on their shape, dimension, and relative position, are analyzed. Studying the visual photographs and the AMRP X-ray CTs of the partially preserved parts, the Functional Reconstruction of Antikythera Mechanism Project team digitally reconstructed and completed some of the lost/destroyed wooden and bronze parts and calculated the dimensions of the plates and the wooden casements of the Antikythera Mechanism ancient prototype.
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The first results during the implementation of the project The Functional Reconstruction of Antikythera Mechanism, The FRAMe Project.
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The present study aims to investigate the astronomical calendar-dial display of the Antikythera Mechanism Front Plate. The design, position and role of the Zodiac ring, are investigated and discussed. Special photographs taken from the... more
The present study aims to investigate the astronomical calendar-dial display of the Antikythera Mechanism Front Plate. The design, position and role of the Zodiac ring, are investigated and discussed. Special photographs taken from the ancient prototype, give us new information about the design and operation of the front dial. From these new findings about the Zodiac ring, we conclude that the user of the mechanism was able to easily perform astronomical calculations at any selected time-of past or future date. Based on the new findings during ''The Functional Reconstruction of Antikythera Mechanism Project'' (FRAMe), we reconstructed the new bronze front plate and we placed it in our functional model of the Antikythera Mechanism.
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After a careful examination of the Antikythera Mechanism CT scans from AMRP, we designed and constructed the mechanical parts that are visible on the scans. We then reconstructed two functional models of the Antikythera mechanism and in... more
After a careful examination of the Antikythera Mechanism CT scans from AMRP, we designed and constructed the mechanical parts that are visible on the scans. We then reconstructed two functional models of the Antikythera mechanism and in this paper we present the observations and the conclusions drawn from their use. The use of these models helped us to understand how the mechanism worked and provided answers in questions regarding the presence and the use of some parts.
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Research Interests: Engineering and Eclipse
A total eclipse swept across Queensland and other sites in northeastern Australia on the early morning of 14 November 2012, local time. We mounted equipment to observe coronal images and spectra during the approximately 2 minutes of... more
A total eclipse swept across Queensland and other sites in northeastern Australia on the early morning of 14 November 2012, local time. We mounted equipment to observe coronal images and spectra during the approximately 2 minutes of totality, the former for comparison with spacecraft images and to fill in the doughnut of imaging not well covered with space coronagraphs. Matching weather statistics, viewing was spotty, and our best observations were from a last-minute inland site on the Tablelands, with some observations from a helicopter at 9000 feet altitude over our original viewing site at Miallo. Only glimpses of the corona were visible at our Port Douglas and Trinity Beach, Cairns, locations, with totality obscured from our sites at Newell and Miallo, though some holes in the clouds provided coronal views from Palm Cove and elsewhere along the coast. Preliminary analysis of the spectra again shows Fe XIV stronger than Fe X, as in 2010 but not earlier, a sign of solar maximum, a...
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Our studies of the solar chromosphere and corona at the 2012 and 2013 eclipses shortly after cycle maximum 24 (2011/2012) of solar activity (see: http://www.swpc.noaa.gov/SolarCycle/) involved radio observations of the 2012 annular... more
Our studies of the solar chromosphere and corona at the 2012 and 2013 eclipses shortly after cycle maximum 24 (2011/2012) of solar activity (see: http://www.swpc.noaa.gov/SolarCycle/) involved radio observations of the 2012 annular eclipse with the Jansky Very Large Array, optical observations of the 2012 total eclipse from Australia, optical observations of the 2013 annular eclipse from Tennant Creek, Australia, and the 3 November 2013 total solar eclipse from Gabon. Our observations are coordinated with those from solar spacecraft: Solar Dynamics Observatory AIA and HMI, Hinode XRT and SOT, SOHO LASCO and EIT, PROBA2 SWAP, and STEREO SECCHI. Our 2012 totality observations include a CME whose motion was observed with a 37-minute interval. We include first results from the expedition to Gabon for the 3 November 2013 eclipse, a summary of eclipse results from along the path of totality across Africa, and a summary of the concomitant spacecraft observations. The Williams College 2012 ...
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We report on our eclipse expedition to Kastellorizo, Greece, in the Dodecanese off the Turkish coast. We observed 3 min 00 sec of totality on 29 March 2006. All our observations worked very well. One of them was high-time-resolution (10... more
We report on our eclipse expedition to Kastellorizo, Greece, in the Dodecanese off the Turkish coast. We observed 3 min 00 sec of totality on 29 March 2006. All our observations worked very well. One of them was high-time-resolution (10 Hz) observations in the coronal green line looking at coronal loops; another was similar observations in the coronal red line; both are to determine among theories of coronal heating and continue earlier reports of excess Fourier power in the 1 Hz range. As we knew from SOHO observations from the day before the eclipse, an active region was stationed right on the east limb and it gave us very suitable loops to study, with pointing in agreement with TRACE. A third set of observations used a very narrow-band filter (Fabry-Perot), with 1/6 angstrom resolution, to make velocity (Doppler) images of the same coronal loops. A fourth set of observations used a telescope we had built to match the size of the now defunct innermost coronagraph on the NASA/ESA S...
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We present new observations concerning the procedure for the reconstruction of the lost eclipse events engraved in the Saros spiral cells of the Antikythera Mechanism. For the reconstructed eclipse events we applied the necessary, albeit... more
We present new observations concerning the procedure for the reconstruction of the lost eclipse events engraved in the Saros spiral cells of the Antikythera Mechanism. For the reconstructed eclipse events we applied the necessary, albeit missing, Draconic gearing of the Antikythera Mechanism [using the Fragment D(raconic)gear r1], which was probably a part of the Mechanism's gearing, representing the fourth lunar motion, the Draconic cycle. The Draconic gearing is very critical for the eclipse prediction and defines whether an eclipse will occur. For our research we created a program which presents the phase of the four lunar cycles-including the position of the Draconic pointer relative to the ecliptic limits. After calibrating the program according to the preserved eclipse events, the lost eclipse events of the Saros spiral were calculated and discussed. The procedure for the calculation of the events' times by using solely the Mechanism based on the pin&slot configuration, is also presented. The eccentricity error of a gear which is preserved on the ancient prototype is analyzed. An experimental setup facilitated the analysis of the mechanical errors of the gears and the study of the motion transmission between gears with triangular teeth. The experimental study of the gears errors revealed the strong impact the Antikythera Mechanism pointers' position has on the results.
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The present study aims to investigate the astronomical calendar-dial display of the Antikythera Mechanism Front Plate. The design, position and role of the Zodiac ring, are investigated and discussed. Special photographs taken from the... more
The present study aims to investigate the astronomical calendar-dial display of the Antikythera Mechanism Front Plate. The design, position and role of the Zodiac ring, are investigated and discussed. Special photographs taken from the ancient prototype, give us new information about the design and operation of the front dial. From these new findings about the Zodiac ring, we conclude that the user of the mechanism was able to easily perform astronomical calculations at any selected time - of past or future date. Based on the new findings during ‘’The Functional Reconstruction of Antikythera Mechanism Project’’ (FRAMe), we reconstructed the new bronze front plate and we placed it in our functional model of the Antikythera Mechanism.
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After studying the design geometry of the Antikythera Mechanism Saros spiral, new critical geometrical/mechanical characteristics of the Back plate design were detected. The geometrical characteristics related to the symmetry of the... more
After studying the design geometry of the Antikythera Mechanism Saros spiral, new critical geometrical/mechanical characteristics of the Back plate design were detected. The geometrical characteristics related to the symmetry of the Antikythera Mechanism design, are independent to the present irregular deformation of the Mechanism parts and were used as calibration points for the Saros spiral cells positional measurements. The Saros cells numbering was recalculated using the calibration points position. A correction of minus one to the currently accepted numbering of the Saros cells was applied. Following the new numbering, a new proper position for the (displaced) Saros pointer axis-g, in graphic design environment was calculated. The measurements were tested on a bronze reconstruction of the Back plate, by the authors. This research leads to a new important result that the Saros does not start in a random or arbitrary date but only when a solar eclipse occurs within a month. Addit...
The present study aims to investigate the astronomical calendar-dial display of the Antikythera Mechanism Front Plate. The design, position and role of the Zodiac ring, are investigated and discussed. Special photographs taken from the... more
The present study aims to investigate the astronomical calendar-dial display of the Antikythera Mechanism Front Plate. The design, position and role of the Zodiac ring, are investigated and discussed. Special photographs taken from the ancient prototype, give us new information about the design and operation of the front dial. From these new findings about the Zodiac ring, we conclude that the user of the mechanism was able to easily perform astronomical calculations at any selected time - of past or future date. Based on the new findings during ‘’The Functional Reconstruction of Antikythera Mechanism Project’’ (FRAMe), we reconstructed the new bronze front plate and we placed it in our functional model of the Antikythera Mechanism.
Research Interests:
After a careful examination of the Antikythera Mechanism computed tomography scans from the Antikythera Mechanism Research Project, we designed and constructed the mechanical parts that are visible on the computed tomography scans. We... more
After a careful examination of the Antikythera Mechanism computed tomography scans from the Antikythera Mechanism Research Project, we designed and constructed the mechanical parts that are visible on the computed tomography scans. We then reconstructed two functional models of the Antikythera Mechanism, and in this paper, we present the observations and the conclusions drawn from their use. The use of these models helped us to understand how the Mechanism worked and provided answers to questions regarding the presence and the use of some parts.
Research Interests:
Research Interests:
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The unplaced Fragment D of the Antikythera Mechanism with an unknown operation was a mystery since the beginning of its discovery. The gear-r1, which was detected on the Fragment radiographies by C. Karakalos, is preserved in excellent... more
The unplaced Fragment D of the Antikythera Mechanism with an unknown operation was a mystery since the beginning of its discovery. The gear-r1, which was detected on the Fragment radiographies by C. Karakalos, is preserved in excellent condition, but this was not enough to correlate it to the existing gear trainings of the Mechanism. The suggestion that this gear could be a part of the hypothetical planet indication gearing is still a hypothesis since no mechanical evidence has been preserved. After the analysis of AMRP tomographies of Fragment D and its mechanical characteristics revealed that it could be part of the Draconic gearing. Although the Draconic cycle was well known during the Mechanism’s era as represents the fourth Lunar cycle, it seems that it is missing from the Antikythera Mechanism. The study of Fragment D was supported by the bronze reconstruction of the Draconic gearing by the authors. The adaptation of the Draconic gearing on the Antikythera Mechanism improves i...
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We observed the 2 July 2019 total solar eclipse with a variety of imaging and spectroscopic instruments recording from three sites in mainland Chile: on the centerline at La Higuera, from the Cerro Tololo Inter-American Observatory, and... more
We observed the 2 July 2019 total solar eclipse with a variety of imaging and spectroscopic instruments recording from three sites in mainland Chile: on the centerline at La Higuera, from the Cerro Tololo Inter-American Observatory, and from La Serena, as well as from a chartered flight at peak totality in mid-Pacific. Our spectroscopy monitored Fe X, Fe XIV, and Ar X lines, and we imaged Ar X with a Lyot filter adjusted from its original H-alpha bandpass. Our composite imaging has been compared with predictions based on modeling using magnetic-field measurements from the pre-eclipse month. Our time-differenced sites will be used to measure motions in coronal streamers.
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After a careful examination of the Antikythera mechanism CTs scans we designed and constructed the elements that are visible on the scans. We then reconstruct two functional models of the Antikythera mechanism and in this paper we present... more
After a careful examination of the Antikythera mechanism CTs scans we designed and constructed the elements that are visible on the scans. We then reconstruct two functional models of the Antikythera mechanism and in this paper we present the observations and the conclusions drawn from their use. The use of these models helped us to understand how the mechanism worked and provided answers to questions regarding the presence of some elements.
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During the total solar eclipse at Akademgorodok, Siberia, Russia, on 1 August 2008, we imaged the flash spectrum with a slitless spectrograph. We have spectroscopically determined the duration of totality, the epoch of the second and... more
During the total solar eclipse at Akademgorodok, Siberia, Russia, on 1 August 2008, we imaged the flash spectrum with a slitless spectrograph. We have spectroscopically determined the duration of totality, the epoch of the second and third contacts and the duration of the flash spectrum. Here we compare the 2008 flash spectra with those that we similarly obtained from the total solar eclipse of 29 March 2006, at Kastellorizo, Greece. Any changes of the intensity of the coronal emission lines, in particularly those of Fe X and Fe XIV, could give us valuable information about the temperature of the corona. The results show that the ionization state of the corona, as manifested especially by the Fe XIV emission line, was much weaker during the 2008 eclipse, indicating that following the long, inactive period during the solar minimum, there was a drop in the overall temperature of the solar corona.
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The flash spectra of the solar chromosphere and corona were measured with a slit-less spectrograph before, after, and during the totality of the solar eclipse of 11 July 2010, at Easter Island, Chile. This eclipse took place at the... more
The flash spectra of the solar chromosphere and corona were measured with a slit-less spectrograph before, after, and during the totality of the solar eclipse of 11 July 2010, at Easter Island, Chile. This eclipse took place at the beginning of Solar Cycle 24, after an extended minimum of solar activity. The spectra taken during the eclipse show a different intensity ratio of the red and green coronal lines compared with those taken during the total solar eclipse of 1 August 2008, which took place toward the end of Solar Cycle 23. The characteristic coronal emission line of forbidden Fe XIV (5303 Å) was observed on the east and west solar limbs in four areas relatively symmetrically located with respect to the solar rotation axis. Subtraction of the continuum flash-spectrum background led to the identification of several extremely weak emission lines, including forbidden Ca XV (5694 Å), which is normally detected only in regions of very high excitation, e.g., during flares or above large sunspots. The height of the chromosphere was measured spectrophotometrically, using spectral lines from light elements and compared with the equivalent height of the lower chromosphere measured using spectral lines from heavy elements.