Showing papers on "Solar eclipse published in 1977"
TL;DR: A weak ionospheric disturbance identified by a minimum in both peak density and total electron content appears to be associated with the eclipse, propagating over a limited distance in the form of a bow wave as discussed by the authors.
34 citations
TL;DR: In this article, the authors reported that large-magnitude periodic fadings during the eclipse of 23 October 1976 indicate that the eclipse is associated with generation of wave disturbance affecting radio-satellite transmissions in the upper VHF.
Abstract: THE localised time-dependent cooling action of the lunar shadow during an eclipse may generate gravity waves at ionospheric heights1,2. The bow wave thus formed would be detected at great distances from the eclipse path. Experimental data in the northern hemisphere from the eclipse on 7 March 1970, indicated the presence of gravity waves in the F-region, deduced from the incoherent backscatter technique3, vertical incidence soundings4, and recordings of the Faraday rotation angle of VHF transmissions from geostationary satellites5. The detected travelling ionospheric disturbance (TID) had the horizontal phase velocity of 400m s−1 (ref. 4) and 620±120 m s−1 (ref. 5). TID was reported to travel north to south4, or 279±25° east of north5. We report here our observations of large-magnitude periodic fadings during the eclipse of 23 October 1976, which indicate that the eclipse is associated with generation of wave disturbance affecting radio-satellite transmissions in the upper VHF. The waves had a 40-km wavelength, and propagated from north to south with a velocity of 556 m s−1.
13 citations
TL;DR: In this article, the authors present the results of measurements made on the angle of arrival of a high frequency radio wave inside the path of totality of an eclipse, which took place on 23 October 1976.
Abstract: CHIMONAS1 predicted that the ‘cooling spot’ of the lunar shadow of an eclipse, which travels at supersonic speeds through the atmosphere, is a continuous source of atmospheric gravity waves. These gravity waves show up by their interaction with the ionosphere and can be detected using standard radio techniques. Total electron content measurements2 in the USA at a distance of several thousand km from the path of totality, detected oscillations which were attributed to a solar eclipse in agreement with the theory of Chimonas3. Measurements made during the 1973 central African eclipse4 failed to detect any oscillations, although these results may have been obscured by the occurrence of a magnetic storm at the same time. We present here the results of measurements made on the angle of arrival of a high frequency radio wave inside the path of totality of an eclipse, which took place on 23 October 1976.
10 citations
TL;DR: Stream drift was recorded in the Acheron River, Victoria, on 23 October 1976, when a total solar eclipse occurred at 1640-1643 h (Eastern Standard Time).
Abstract: Stream drift was recorded in the Acheron River, Victoria, on 23 October 1976. A total solar eclipse occurred at 1640-1643 h (Eastern Standard Time). No noticeable effect on the number or types of animals drifting was observed.
9 citations
TL;DR: In this article, a preliminary analysis of the declination variations recorded in the path of totality at stations H (Millicent, S.A.) and J (Merimbula, N.S.W.).
Abstract: SOLAR eclipses may cause geomagnetic effects by disturbing the flow of electric currents in the ionosphere1,2, and a number of observations of this phenomenon have been made in recent years3,4. To monitor any magnetic effects of the eclipse of 23 October 1976, we operated recording magnetometers at 10 sites in central and eastern Australia (Fig. 1); these instruments were in addition to the regular observatories of the Bureau of Mineral Resources near Perth and Melbourne. We present here a preliminary analysis of the declination variations recorded in the path of totality at stations H (Millicent, S.A.) and J (Merimbula, N.S.W.).
7 citations
31 Dec 1977
TL;DR: In this paper, total ionospheric electron content (TEC) has been determined from the measurements of the Faraday rotation of a plane polarized wave that have been returned from the geostationary satellite ATS 6 transmitting at a frequency of 140 MHz.
Abstract: Total ionospheric electron content (TEC) has been determined from the measurements of the Faraday rotation of a plane polarized wave that have been returned from the geostationary satellite ATS 6 transmitting at a frequency of 140 MHz. The results of the computations have been presented in the form of diurnal curves in order to investigate the effect of the solar eclipse of 29 April 1976 on the TEC over Ankara longitudes.
2 citations
1 citations
1 citations
TL;DR: In this paper, the light intensity in the zenith, obtained during the annular solar eclipse of April 29, 1976 are given in three wavelength bands (centered on λ's 4800, 5400 and 6100 A).
Abstract: Measurement of the light intensity in the zenith, obtained during the annular solar eclipse of April 29, 1976 are given in three wavelength bands (centered on λ's 4800, 5400 and 6100 A). The observed differences in the three wavelength regions have been examined and compared with calculations taking into account limb darkening.
01 Jan 1977
TL;DR: One of the Ugaritic texts of the Second Millennium BC describes a total eclipse of the Sun as mentioned in this paper, and the date is established as 1375 BC, May 3, 2014.
Abstract: One of the Ugaritic texts of the Second Millennium BC describes a total eclipse of the Sun. The date is established as 1375 BC, May 3.
TL;DR: The usual method for correcting sunspot intensity measurements for stray light has been applied in the case of the partial solar eclipse of 30 June, 1973, where a sunspot was partly obscured as well as the solar disc as discussed by the authors.
Abstract: The usual method for correcting sunspot intensity measurements for stray light has been applied in the case of the partial solar eclipse of 30 June, 1973, where a sunspot was partly obscured as well as the solar disc. In the first order, assuming a circular sunspot structure and neglecting the scattering, the intensity at the centre is calculated for wavelengths λ1=5300 A and λ2=6070 A the apparent and the true intensities obtained are, respectively, 0.120±0.015 and 0.083±0.008 for λ1 and 0.161±0.017 and 0.124±0.012 for λ2.