Talk detail

Participant	Sigismondi, Costantino
Institution	ICRA - p.le A. Moro 5 - Rome - - Italy

Session	BN4	Accepted		Order	Time
Talk	Oral abstract	Title	Observational Accuracy of Novae and Supernovae From Naked Eye To General Relativistic Standard: A Balance Over Thousand SGQ Observations Sent To AAVSO.
Coauthors
Abstract	The theory of General Relativity deals with very accurate measurements that show significant divergences from Newtonian predictions only with speeds near to the velocity of light. An introduction for educational purposes, based on naked eye photometry, deals with the radiation near collapsing star's shells like novae and supernovae. The theme of accuracy is drafted from entry level observations to the precision of professional data, often of public domain on the web. Thousand observations of variable stars, included the type 1a SN2014J, the Nova Del 2013 and the Nova Cen 2013, sent to the AAVSO by the author, with SGQ code, during the period 1998-2015 are analyzed to increase the photometric accuracy, in the occasion of the International Year of Light 2015.
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Session	PT5	Accepted		Order	Time
Talk	Oral abstract	Title	Transits Of Venus And Solar Diameter Measures From Ground: Method And Results From Athens (2004) And Huairou (2012)
Coauthors
Abstract	The variation of the solar diameter in time and in position angle has implications in astrophysics and in general relativity, as the long series of studies attest. The Transits of Venus in 2004 and 2012 have been carefully studied because of the rarity of the phenomenon and its historical importance due the AU measure and to the discovery of Venus atmosphere. The characterization of Venus atmosphere and the measure of the solar diameter to the milliarcsecond level of precision have been studied also from satellite images. The results of the solar diameter measurements made with the observations in Athens (2004) and at the Huairou Solar Observing Station in China (2012) are presented. The topic of the oblateness of the Sun at sunset and its intrinsic value is drafted to introduce the general public to the relativistic relevance of measuring the solar figure, in the occasion of the International Year of Light 2015.
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Session	HR1	Accepted		Order	Time
Talk	Oral abstract	Title	The Eddington's Eclispe And Possible Replica Of The Experiment Of Light Bending
Coauthors
Abstract	The success of the first measurement of the light bending by the solar gravitational field is due to the particular stellar field during the Eddington eclipse. In the 1919 total eclipse the Sun was near the Hyades, giving the opportunity to measure the gravitational bending of the light to the astronomers in two expeditions in Brazil, Sobral, and on the Principe Island in the Atlantic Ocean. This stellar field has geometrical properties particularly adapt to this experiment of General Relativity, and a novel replica of this observation is presented and discussed in the context of the International Year of Light 2015.
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Session	PT5	Accepted		Order	Time
Talk	Oral abstract	Title	Optical Deformations in Solar Glass Filters for High Precision Astrometry
Coauthors
Abstract	Measuring the solar diameter at all position angles gives the complete figure of the Sun. Their asphericities have implications in classical physics and general relativity, and the behavior of the optical systems used in the direct measurements is to be known accurately. A solar filter is a plane-parallel glass with given absorption, and here we study the departures from the parallelism of the faces of a crystal slab 5 mm thick, because of static deformations. These deformations are rescaled to the filter's dimensions. Related to the Solar Disk Sextant experiment and to the Reflecting Heliometer of Rio de Janeiro a simplified model of the influences of the inclination between the external and the internal surfaces of a glass solar filter, is discussed.
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