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Related papers: Ground-based measurements of solar diameter

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Solar radius measurements and their variations -- if any -- are a difficult problem that has vexed researchers for decades. In this paper, we have attempted to clarify the various ways of expressing the definition ''solar diameter'', from a…

Solar and Stellar Astrophysics · Physics 2026-05-25 Jean-Pierre Rozelot , Alexander Kosovichev

The Total Solar Irradiance varies over a solar cycle of 11 years and maybe over cycles with longer period. Is the solar diameter variable over time too? We introduce a new method to perform high resolution astrometry of the solar diameter…

Solar and Stellar Astrophysics · Physics 2012-02-20 Andrea Raponi , Costantino Sigismondi , Konrad Guhl , Richard Nugent , Andreas Tegtmeier

The lifetime of a satellite is limited, and its calibration may be not stable, it is necessary to continue ground-based measures of the solar diameter with methods less affected by atmospheric turbulence, and optical aberrations: planetary…

Instrumentation and Methods for Astrophysics · Physics 2013-01-21 Costantino Sigismondi

The modern methods of measurement of the solar diameter and oblateness are reviewed. Either ground-based or balloon-borne and satellite measurements are considered. The importance of solar astrometry for General Relativity is emphasized,…

Solar and Stellar Astrophysics · Physics 2015-05-28 Costantino Sigismondi

Solar astrometry deals with the accurate measumerent of the solar diameter, and in general with the measurement of the shape of the Sun. During the last decades several techniques have been developed to monitor the radius and the irradiance…

Solar and Stellar Astrophysics · Physics 2015-06-03 Costantino Sigismondi

A discussion of the solar diameter and its variations must be linked to the limb darkening function (LDF). We introduce a new method to perform high resolution astrometry of the solar diameter from the ground, through the observations of…

Solar and Stellar Astrophysics · Physics 2013-02-15 Andrea Raponi

In order to perform high resolution astrometry of the solar diameter from the ground, through the observations of eclipses, the study of the limb darkening profile is described. Knowing the profile of the solar limb is useful both to…

Solar and Stellar Astrophysics · Physics 2015-06-03 Andrea Raponi , Costantino Sigismondi , Konrad Guhl , Richard Nugent , Andreas Tegtmeier

The variation of the solar diameter is the subject of hot debates due to the possible effect on Earth climate and also due to different interpretations of long period solar variabilities, including the total solar irradiance. We shortly…

Solar and Stellar Astrophysics · Physics 2012-07-10 Koutchmy Serge , Bazin Cyril , Prado Jean-Yves , Lamy Philippe , Rocher Patrick

The diameter of the Sun has been measured using Baily's beads during central eclipses, observed with portable telescopes. A blend of tiny emission lines produced in the first several hundred kilometers above the photosphere gives a light…

Solar and Stellar Astrophysics · Physics 2013-02-06 Costantino Sigismondi , Andrea Raponi , Cyril Bazin , Richard Nugent

The size of the diameter of the Sun has been debated for a very long time. First tackled by the Greek astronomers from a geometric point of view, an estimate, although incorrect, has been determined, not truly called into question for…

Solar and Stellar Astrophysics · Physics 2016-09-12 Jean Pierre Rozelot , Alexander G. Kosovichev , Ali Kilcik

We introduce a new method to perform high resolution astrometry of the solar diameter from the ground, through the observations of eclipses. A discussion of the solar diameter and its variations is linked to the Limb Darkening Function…

Solar and Stellar Astrophysics · Physics 2015-06-03 Andrea Raponi , Costantino Sigismondi , Konrad Guhl , Richard Nugent , Andreas Tegtmeier

The measurement of the Sun's diameter has been first tackled by the Greek astronomers from a geometric point of view. Their estimation of ~1800", although incorrect, was not truly called into question for several centuries. The first…

Solar and Stellar Astrophysics · Physics 2018-04-20 J. P. Rozelot , A. G. Kosovichev , A. Kilcik

A sunset over the sea surface offers the possibility to chronometrate a solar transit across the horizon. The vertical solar diameter is proportional to the duration of the sunset, the cosine of the azimuth and the cosine of the latitude of…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Costantino Sigismondi

The uncertainty of measurement of solar diameter is depending on the observational time scale. Full-disc images of SDO/HMI and the images from ground observations in Huairou Solar Observing Station have been analyzed to get the values of…

Solar and Stellar Astrophysics · Physics 2015-06-11 Xiaofan Wang , Costantino Sigismondi

We review techniques for measuring stellar oscillations in solar-type stars. Despite great efforts, no unambiguous detections have been made. A new method, based on monitoring the equivalent widths of strong lines, shows promise but is yet…

Astrophysics · Physics 2007-05-23 Hans Kjeldsen , Timothy R. Bedding

Two methods are used to observationally determine the solar radius: One is the observation of the intensity profile at the limb, the other one uses f-mode frequencies to derive a 'seismic' solar radius which is then corrected to optical…

Astrophysics · Physics 2009-11-13 Margit Haberreiter , Alexander G. Kosovichev , Werner Schmutz

The unprecedented precision of broadband stellar photometry achieved with the planet-hunting missions CoRoT and \textit{Kepler} initiated a new era in examining the magnetically-driven brightness variations of hundreds of thousands of…

Solar and Stellar Astrophysics · Physics 2021-06-25 Nina-Elisabet Nèmec

We show in this paper that the changes of the solar diameter in response to variations of large scale magnetic fields and turbulence are not homologous. For the best current model, the variation at the photospheric level is over 1000 times…

Astrophysics · Physics 2016-08-16 Sabatino Sofia , Sarbani Basu , Pierre Demarque , Linghuai Li , Gerard Thuillier

The measurement of the solar diameter is introduced in the wider framework of solar variability and of the influences of the Sun upon the Earth's climate. Ancient eclipses and planetary transits would permit to extend the knowledge of the…

Instrumentation and Methods for Astrophysics · Physics 2012-11-26 Costantino Sigismondi

The Solar Diameter Monitor measured the duration of solar meridian transits during the 6 years 1981 to 1987, spanning the declining half of solar cycle 21. We have combined these photoelectric measurements with models of the solar…

Astrophysics · Physics 2008-11-26 T. M. Brown , J. Christensen-Dalsgaard
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