Topic
Solar eclipse
About: Solar eclipse is a research topic. Over the lifetime, 2737 publications have been published within this topic receiving 22625 citations.
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TL;DR: In this article, the period of a torsion pendulum was measured during the solar eclipse of 22 July 1990 in Finland and the relative change in the pendulum's period associated with the eclipse was found to be less than 4.3
Abstract: During the solar eclipse of 22 July 1990 in Finland the period of a torsion pendulum was measured. In previous experiments of this kind [Phys. Rev. D 3, 823 (1971)] a considerable increase was found in the period of the pendulum during the solar eclipse. In our experiment, however, no significant change in the period was observed. The relative change in the pendulum's period associated with the eclipse was found to be less than 4.3\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$ (90% confidence).
14 citations
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TL;DR: The LCR-G402 gravimeter equipped with a feedback system and a digital data acquisition system scanned gravity and pressure every second around the total solar eclipse of 11 July 1991 in Mexico City as discussed by the authors.
Abstract: Observations of gravity and atmospheric pressure variations during the total solar eclipse of 11 July 1991 in Mexico City are presented. An LCR-G402 gravimeter equipped with a feedback system and a digital data acquisition system scanned gravity and pressure every second around the totality. On the pressure record an oscillation, starting at the totality, with a peak to peak amplitude of 0.5 hPa and a periodicity of 40 to 50 min, can clearly be seen. This oscillation results from the thermal shock wave produced by the Moon shadow travelling at supersonic speed. At the 0.1 μGal (1 nm · s−2) level all gravity perturbations are explained by the atmospheric pressure effect.
14 citations
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TL;DR: In this paper, a sky brightness monitor (SBM) was used for the site survey of Chinese giant solar telescope (CGST) in Dali City, Yunnan, on 15 January 2010.
Abstract: For the future development of Chinese Giant Solar Telescope (CGST) in Western China, a new sky brightness monitor (SBM) has been produced for the site survey for CGST. To critically examine the performance and sensitivity of SBM, we used it in the observation of the annular solar eclipse in Dali City, Yunnan, on 15 January 2010. The observation met good weather conditions with an almost clear sky during the eclipse. The SBM measurement translates into the solar illuminance changes at a level of 2.4x10(-4) I s(-1) during the eclipse. The time of the minimal sky brightness in the field of view (FOV) is found consistent with the time of maximum eclipse. Two local sky regions in the FOV are chosen to make a time series of the calibrated skylight profiles. The evolution of the sky brightness thus calibrated also shows good consistency with the eclipse, particularly between the second and the third contacts. The minimal sky brightness in each local sky region took place within half a minute from the corresponding predicted contact time. Such small time delays were mainly caused by occasional cirri. The minimal sky brightness measured during the eclipse is a few millionths of I (aS (TM)) with standard deviation of 0.11 millionths of I (aS (TM)). The observation supports that the single-scattering process (optically thin conditions) is the main contributor to the atmospheric scattering. We have demonstrated that many important aerosol optical parameters can be deduced from our data. We conclude that the new SBM is a sensitive sky photometer that can be used for our CGST and coronagraph site surveys.
14 citations
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TL;DR: It has been definitely established that the ionosphere responsible for carrying radio waves round the curved surface of the earth is divided into two clearly distinguishable regions as discussed by the authors, and the nature of the ionising agencies producing these two different layers is not yet definitely known.
Abstract: IT has been definitely established that the ionosphere responsible for carrying radio waves round the curved surface of the earth is divided into two clearly distinguishable regions1,2 The lower—the classical Kennelly-Heaviside or the E layer—is situated at a height of about 90 km, and the upper —the Appleton or the F layer—is situated at a height of about 200 km The nature of the ionising agencies producing these two different layers is, however, not yet definitely known
14 citations
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TL;DR: In this paper, the emission line resonance polarization in Fe xiii λ10747 at the total solar eclipse of 12 November 1966 has been observed, ranging from near zero at the limb to 80 % and higher at 1.6 R⊙.
Abstract: Observations are presented of emission line resonance polarization in Fe xiii λ10747 at the total solar eclipse of 12 November 1966. Useful data, with angular resolution 15″, describe three quadrants of the corona from 1.08 R⊙ to a maximum of 1.6 R⊙. The direction of the electric vector of observed polarization is perpendicular to the solar limb, to the limits of accuracy of measurement, in at least 74% of all cases. Departures in the other points are consistent with the magnetic depolarization expected from the non-radial fields of streamers. Polarizations observed range from near zero at the limb to 80 % and higher at 1.6 R⊙. Averaged polarization is highest in non-streamer regions, where above 1.2 R⊙ it suggests pure radiative excitation of the λ10747 line. Below 1.2 R⊙, and in a dense streamer, the polarization is significantly depressed, indicating dominant collisional excitation of the line wherever the electron density exceeds 50 × 106 cm−3.
13 citations