Showing papers on "Solar eclipse published in 1976"
44 citations
43 citations
TL;DR: The battle of Salamis can be dated with a high degree of certainty as discussed by the authors, and it is known that at some point while building the wall, Cleombrotus considered giving chase to the Persian army.
Abstract: The battle of Salamis can be dated with a high degree of certainty. Probably about the time of that battle, Cleombrotus was at the Isthmus, constructing the defences there (Hdt. 8. 71. 1). At some point while building the wall, he considered giving chase to the Persian army. When his sacrifice was answered by a solar eclipse, he took this as a bad omen and immediately returned to Lacedaemon (9. 10. 2–3). The eclipse visible to Cleombrotus could only have been that of 2 October 480. Now it is generally supposed that Cleombrotus would not have thought to abandon the construction of the wall and pursue Xerxes unless the latter had just begun his retreat from Athens. Thus, as Herodotus says that a few days () after the battle of Salamis Xerxes withdrew from Attica (8. 113. 1), the battle of Salamis probably occurred before 2 October 480.
31 citations
TL;DR: A photometric and colorimetric analysis of a color picture of the very inner solar corona, near the South pole region, is performed in this paper. But the results are limited to a half width of 1.67 cm.
Abstract: A photometric and colorimetric analysis of a color picture of the very inner solar corona, near the South pole region, is performed. Dimensions and average electron densities of both chromospheric and very fine resolved coronal spikes are deduced. For the coronal spike a half width of 1″.67 is measured, the estimate of electron density yields ne = 1010 cm−3. Some conclusions are attempted on the light of a simultaneously observed spectrum of the same region which appeared to be a “disappearing coronal hole.” The observations seem to support the concept of a “striated” corona.
27 citations
TL;DR: In this paper, the authors analyzed the Doppler data of F layer reflection during the solar eclipse day and control days by using a numerical Fourier transform, and they found that the internal gravity waves seem to affect the electron density in the F layer, although it is hard to confirm the existence of the gravity waves because the period is difficult to distinguish from the periods of the medium-scale TID's in F region.
Abstract: Periodic variations observed from the Doppler data of F layer reflection during the solar eclipse day and control days are analyzed by using a numerical Fourier transform. The gravity waves of the 22-min period may be generated by the solar eclipse, although it is hard to confirm the existence of the gravity waves because the period is difficult to distinguish from the periods of the medium-scale TID's in the F region. The internal gravity waves seem to affect the electron density in the F layer.
16 citations
01 Jun 1976
11 citations
TL;DR: A search for eclipse-induced Lamb waves was made with ground-level pressure sensors at two sites during the eclipse of 11 May 1975 as discussed by the authors, and cross-correlation analysis resulted in a preliminary upper limit being placed on the magnitude of the waves.
Abstract: A search for eclipse-induced Lamb waves was made with ground-level pressure sensors at two sites during the eclipse of 11 May 1975. Cross-correlation analysis resulted in a preliminary upper limit being placed on the magnitude of the waves.
9 citations
TL;DR: In this article, the authors used a Tektronix J20/7J20 rapid scanning silicon vidicon spectrometer for ground-based eclipse studies of infrared coronal lines.
7 citations
Journal Article•
6 citations
TL;DR: In this article, it was shown that during a solar eclipse, the cool shadow of the Moon moving with supersonic speed through the Earth's atmosphere should generate bow waves, which were recorded after the eclipse of March 7, 1970, and were regarded as possible verification of Chimonas and Hines's suggestion.
Abstract: CHIMONAS and Hines1 suggested that during a solar eclipse the cool shadow of the Moon moving with supersonic speed through the Earth's atmosphere should generate bow waves. Upper atmospheric disturbances, having quasi-periods of some 20 min, were recorded2,3 after the eclipse of March 7, 1970, and were regarded as possible verification of Chimonas and Hines's9 suggestion. Other observations4,5 following the eclipse of June 30, 1973, failed to detect such disturbances. The eclipse of October 23, 1976, will provide another opportunity in attempting to record eclipse-generated atmospheric disturbances.
6 citations
TL;DR: In this article, the authors reported the results of a conventional probing (ionograms), bringing more evidence of the relation between the eclipse and the ionospheric perturbations, which could be generated by gravity waves launched by the solar eclipse of the 30 June 1973
TL;DR: In this article, the authors measured the direction of polarization in the outer corona with the classical method of measuring polarization with a small number of photographs and analyzed the coronal hole in the south-west quadrant.
Abstract: Polarigraphic observations of the 7 March, 1970 eclipse were made at Miahuatlan (Mexico) with a camera of 120 cm focal length. A polarizing filter in front of the objective could be adjusted at 8 different positions, 22.5° apart. Reduction of eight photographs of the white light corona yields polarization at 72 position angles and from r = 1.1 up to 2.1. High polarization which cannot be explained with Thomson scattering was not observed. An analysation of the measuring accuracy shows, that it is not possible to determine exactly the direction of polarization in the outer corona with the classical method of measuring polarization with a small number of photographs. The coronal hole in the south-west quadrant is analysed. The low intensity and polarization can be explained by a hole with an extent in longitude between 1 and 2 times its extent in latitude and with a minimum electron density between 0 and 0.3 of that outside the hole.
01 Mar 1976
TL;DR: Baily beads were observed from near the northern limit of totality during the eclipse of June 20, 1974; no attempt of identification was made at the time of observation as mentioned in this paper, and the observations were analysed to identify the features of the lunar profile which gave rise to the beads observed.
Abstract: Baily beads were observed from near the northern limit of totality during the eclipse of June 20, 1974; no attempt of identification was made at the time of observation. The observations were analysed to identify the features of the lunar profile which gave rise to the beads observed. They were then analysed to derive corrections to the relative positions of the Sun and Moon, and to investigate certain features of the lunar profile.
TL;DR: In this paper, a multifrequency oblique-incidence experiment performed during the 10 July 1972 total solar eclipse is described and a definite correlation of VLF phase, HF signal strength and geomagnetic field behavior on eclipse day is demonstrated.
TL;DR: In this paper, the authors examined the time sequence of line profiles of Fe xiv emission obtained at the 1965 solar eclipse for temporal variations of intensity and profile and found that two regions with intensity and profiles line width variations are found.
Abstract: The time sequence of line profiles of Fe xiv emission obtained at the 1965 solar eclipse is examined for temporal variations of intensity and profile. Although no variations are found in some regions examined, two regions with intensity and profile line width variations are found. A simple temperature wave is consistent with observations.
TL;DR: It seems that the incidence of eye injuries could be reduced because some small part of the population will watch the eclipse regardless of all warnings not to, and only if safe filters are readily available could these people avoid loss of vision.
Abstract: The October 1976 total solar eclipse will be well placed for observation by millions of Australians. Previous eclipses have produced numerous cases of eye injury despite well-organised and extensive campaigns to counter the problem by advice not to watch the eclipse except by the pinhole projection method. Misuse of this method has itself led to many cases of retinal damage. It appears that although some filters currently available to the public might be safe for watching the eclipse, others are not and individuals have no easy way of ascertaining the degree of safety. If a large number of filters that are guaranteed to be safe are made readily available to the public it seems that the incidence of eye injuries could be reduced because some small part of the population will watch the eclipse regardless of all warnings not to, and only if safe filters are readily available could these people avoid loss of vision.
TL;DR: The solar eclipse to be experienced in Australia on 23rd October, 1976 is outlined, the clinical entity of solar photo-retinitis is described and a programme aimed at its prevention is introduced.
Abstract: Solar Eclipse over Australia, 23rd October, 1976.
Eclipse of the sun by the moon is a spectacular phenomenon and the delight of professional and amateur astronomers. Unfortunately, a solar eclipse is always associated with permanent damage to vision in a surprisingly large number of people, mainly children.
Eclipse blindness results from a chorio-retinal burn as a consequence of direct and usually deliberate exposure of the macular region of the eye to intense solar radiation. The only rational means of dealing with eclipse blindness is by prevention as there is no effective means of its treatment.
This report outlines the solar eclipse to be experienced in Australia on 23rd October, 1976, describes the clinical entity of solar photo-retinitis and Introduces a programme aimed at its prevention.
01 Oct 1976
TL;DR: The ion-pair production rate due to x-rays and EUV radiation is a function of latitude, time of day, solar declination, and the solar sunspot cycle.
Abstract: : The sources of ionization in the mesosphere and stratosphere may be placed in three categories: solar radiation (photons), galactic cosmic rays, and precipitating energetic particles of solar and terrestrial origin and modulation. The ion-pair production rate Q (ion pairs per cubic centimeter per second) due to x-rays and EUV radiation is a function of latitude, time of day, solar declination, and the solar sunspot cycle. Solar radiation dominates the Q term in the upper mesosphere during the day. Galactic cosmic rays are the major source of ion pairs at night throughout the stratosphere and lower mesosphere and even into the upper mesosphere during geomagnetically quiet conditions. The Q term due to galactic cosmic rays also displays a dependence on latitude and the solar cycle. Energetic particles (electrons 40 keV, protons 1 MeV, alpha particles 5 MeV) can be the dominant source of ion pairs for short times in the stratosphere and mesosphere, competing with even solar radiation under some circumstances. The effects are more prominent at higher latitudes, particularly for protons.
TL;DR: The silicon vidicon spectrometer will be useful in both eclipse and noneclipse solar observing to map the coronal ir spectrum and also to study the [Fe XIII] ir and interlocking uv lines.
Abstract: A rapid-scanning silicon vidicon spectrometer is described; its sensitivity extends from 300 nm to 1080 nm, where even at that wavelength it has enough sensitivity to allow observation under eclipse conditions of a pair of forbidden spectral lines from twelve-times ionized iron that are sensitive indicators of the electron density in the solar corona Past observational work on these ir lines is reviewed, and our vidicon observations made during the 1973 total solar eclipse are discussed The vidicon target, the scanning procedure, and the advantages of the spectrometer are described At the 1973 eclipse, the 10747-nm line was detected and an upper limit set for the 10798-nm line at a height of 14 solar radii The resultant limit to the ratio of intensities gives electron densities in agreement with those derived from other methods and is consistent with observations made at lower heights; this indicates that the only previous eclipse observation of the ratio at this height was contaminated by scattered light Our 1973 eclipse observations were limited by the high ambient temperature of the vidicon, by the less-than-optimum match of the focal ratios of the telescope and spectrometer optics, and by problems with the pointing during totality These difficulties can be overcome, and the silicon vidicon spectrometer will be useful in both eclipse and noneclipse solar observing to map the coronal ir spectrum and also to study the [Fe xiii] ir and interlocking uv lines
TL;DR: The prediction of solar eclipse coronal structures began in 1968 as discussed by the authors as an offshoot from suggestions by Chapman2 and Gold3 that the magnetic field in the vicinity of the Sun could be calculated.
Abstract: PREDICTION of solar eclipse coronal structures began in 19681 as an offshoot from suggestions by Chapman2 and Gold3 that the magnetic field in the vicinity of the Sun could be calculated. A degree of success was achieved with these early attempts1,4–6. Cowling7 states that “a sketch showing the corona observed at the eclipse … agrees well with the prediction; had Schatten drawn his streamers more nearly radial, the agreement would have been almost perfect”.
01 Dec 1976
TL;DR: There is no fail-safe way of looking at solar eclipse directly by the uninitiated and inexperienced, without the aid of highly sophisticated optical apparatus, and to find a failsafe method of obtaining total public acceptance of this conclusion is inconsistent with the behavioural attribu:es of some individuals.
Abstract: A solar eclipse will occur over the most densely populated region of the Australian continent on October 23, 1976. E-Day has already attracted the attention of the eye-care professions and will probably attract even more attention from the media and the public as it draws nearer. A variety of simple devices and methods of viewing solar eclipses has already been suggested. Notwithstanding the invention of improved inexpensive solar filters, there is no fail-safe way of looking at solar eclipse directly by the uninitiated and inexperienced, without the aid of highly sophisticated optical apparatus. To find a failsafe method of obtaining total public acceptance of this conclusion is inconsistent with the behavioural attribu:es of some individuals.
01 Feb 1976
TL;DR: In this paper, the Apollo spacecraft successfully occulted the solar disk from the field of view of a camera mounted in the Soyuz spacecraft while performing a spacecraft separation maneuver to permit the outer solar corona to be viewable by the camera.
Abstract: On July 19, 1975, the Apollo spacecraft successfully occulted the solar disk from the field of view of a camera mounted in the Soyuz spacecraft while performing a spacecraft separation maneuver to permit the outer solar corona to be viewable by the Soyuz camera. The camera operated automatically, and 55 frames were developed for scientific analysis.