Showing papers on "Solar eclipse published in 1971"
TL;DR: In this article, a collaborative rocket experiment carried out during the solar eclipse on 7 March 1970, measurements have been made of the brightness of Lyman α from the corona, at heights between 5 × 104 and 5 × 105 km above the limb.
Abstract: As a result of a collaborative rocket experiment carried out during the solar eclipse on 7 March, 1970, measurements have been made of the brightness of Lyman α from the corona, at heights between 5 × 104 and 5 × 105 km above the limb. The emission is shown to occur primarily through the resonance scattering of chromospheric Lyman α from the residual neutral hydrogen in the corona. Both the absolute value and radial fall-off of the brightness agree well with calculations based on solar density models. The Lyman α emission has similar variations around the limb to the white light corona, showing in particular an equatorial enhancement.
90 citations
TL;DR: In this article, the times required for the torsion pendulum to rotate through a given fixed part of its path, involving both clockwise and counterclockwise motions, on its first swing from rest were observed during the course of the eclipse as well as in the hours just preceding and just following the eclipse itself.
Abstract: During the solar eclipse of 7 March 1970, readings were taken and recorded electronically of the times required for the torsion pendulum to rotate through a given fixed part of its path, involving both clockwise and counterclockwise motions, on its first swing from rest. Significant variations in these times were observed during the course of the eclipse as well as in the hours just preceding and just following the eclipse itself. Between the onset of the eclipse and its midpoint there is a steady increase in the observed times. After the midpoint the times decrease suddenly and level off promptly to values considerably greater than those observed before the eclipse. Furthermore, before the eclipse there is a periodic variation in these times. This strange periodicity was essentially repeated two weeks later at the same hours, though the actual values were somewhat greater than the earlier ones. These increases in actual values exceed by a factor of ${10}^{5}$ those that can be explained by the attraction of the moon due to its change in position relative to the sun and earth. All this leads to the conclusion that classical gravitational theory needs to be modified to interpret these experimental facts.
63 citations
TL;DR: Chorioretinal temperature increases produced by solar observations are computed digitally using the spectral characteristics of solar radiation and the spectral transmittances of the atmosphere, atmospheric water vapor and ocular media.
57 citations
TL;DR: In this article, the absolute intensity of the inner solar corona was obtained at the total solar eclipse of 30 May 1965 using a fast spectrograph with a circular slit that recorded the spectrum from λ 3000 to λ 9000 at all position angles around the limb simultaneously.
Abstract: A series of spectrograms of the inner solar corona were obtained at the total solar eclipse of 30 May 1965 using a fast spectrograph with a circular slit that recorded the spectrum from λ3000 to λ9000 at all position angles around the limb simultaneously. In this paper absolute intensity is given as a function of position angle for the stronger lines and the continuum. In the coronal enhancement or condensation centered at heliocentric position angle 293°, absolute intensity is given for 34 forbidden emission lines and the continuum.
57 citations
TL;DR: Chimonas and Hines as discussed by the authors predicted that a supersonic shock within the atmosphere would be followed by ionospheric disturbances observable from some distance, and such effects were observed during the total solar eclipse of March 7, 1970.
Abstract: Chimonas and Hines1 predicted that a supersonic shock within the atmosphere would be followed by ionospheric disturbances observable from some distance. Such effects were observed during the total solar eclipse of March 7, 1970 (ref. 2). Similar ionospheric effects are to be expected when a large missile and its exhaust plume travel with supersonic velocity close to ionospheric heights. This effect was observed at Fort Monmouth, New Jersey, on January 31, 1971, after the Apollo 14 launching. Ionograms taken from vertical sounding at the Red Hill Station (74 : 07 : 52 W long.; 40 : 23 : 25 N lat.) every 5 min have been converted to true-height electron-density profiles (Fig. 1). Each curve in the figure describes the true height variation of a noted plasma frequency (MHz). Since sporadic-E was present during part of the experiment, the figure is restricted to F-region data. Three successive compressions or undulations within the lower part of the region are indicated. The second undulation, however, is noticeable throughout the entire bottomside region.
52 citations
TL;DR: In this article, daily Mgx λ 625 spectroheliograms acquired by the Harvard College Observatory experiment on OSO-6 for a 28-day period centered on 7 March, 1970, the date of a well-observed total solar eclipse were used to construct maps of the variation across the solar disk of the electron density at the base of the corona.
Abstract: We have analyzed daily Mgx λ 625 spectroheliograms acquired by the Harvard College Observatory experiment on OSO-6 for a 28-day period centered on 7 March, 1970, the date of a well-observed total solar eclipse These data are used to construct maps of the variation across the solar disk of the electron density at the base of the corona The correspondence of high and low density regions with regions of enhanced and reduced emission in white light and Mgx pictures made during or near the time of the eclipse are described
33 citations
TL;DR: The spectral distributions in terms of an effective blackbody temperature for the range 4100-8000 A were 5000 K, 9000 K, and 11,000 K for the twilight, control day sky, and totality, respectively, indicating a shift toward the shorter wavelength at totality.
Abstract: Zenith sky brightness at totality was observed to be about four orders of magnitude lower than that for a normal day sky. The spectral distributions in terms of an effective blackbody temperature for the range 4100-8000 A were 5000 K, 9000 K, and 11,000 K for the twilight, control day sky, and totality, respectively, indicating a shift toward the shorter wavelength at totality. The polarization measured in the sun's vertical plane 90 degrees away from the sun was 4% and 0.6% at 4750 A and 6000 A, respectively. Both colors showed a change in the plane of polarization of about 50 degrees at the time of totality. From the change in the plane of polarization it is estimated from the primary component reduced by about an order of magnitude at totality of the eclipse.
24 citations
TL;DR: Electron content spatial and temporal variation during ionospheric storm of 8 March 1970 after total solar eclipse after total eclipse as mentioned in this paper, which was the first one after the solar eclipse.
Abstract: Electron content spatial and temporal variation during ionospheric storm of 8 March 1970 after total solar eclipse
22 citations
TL;DR: A survey of the infrared coronal spectrum between 1 μ and 3 μ was made from a high altitude aircraft during the 7 March, 1970, solar eclipse as discussed by the authors, and the observations were made with a Fourier transform spectrometer and were confined to the outer chromosphere and inner corona.
Abstract: A survey of the infrared coronal spectrum between 1 μ and 3 μ was made from a high altitude aircraft during the 7 March, 1970, solar eclipse. The observations were made with a Fourier transform spectrometer and were confined to the outer chromosphere and inner corona. In addition to well known chromospheric lines of Hi and Hei, nine additional lines were seen. Evidence is presented for the tentative assignment of these lines to forbidden transitions in highly ionized atoms of magnesium, aluminum, silicon, sulphur, and chromium.
19 citations
TL;DR: In this paper, the radial and tangential polarization of the solar corona for the 1970, March 7, solar eclipse was photographed using a neutral density filter and rotating linear polaroid sectors to allow the polarization structure to be seen from 1 to 6 solar radii.
Abstract: Photographic observations were obtained of the radial and tangential polarization of the solar corona for the 1970, March 7, solar eclipse The corona was photographed using a neutral density filter and rotating linear polaroid sectors to allow the polarization structure to be seen from 1 to 6 solar radii Anomalously high polarizations were found for structures with the E-tangential intensity being predominantly larger than the E-radial intensity These structures are generally filamentary in nature and radial in direction One case with a high radial polarization was also found The photographs were calibrated accurately against the Earth shine from the Moon Possible source mechanisms are discussed that may explain this new component in the solar corona Most sources may be ruled out on physical grounds One possibility appears to be synchrotron radiation from 10 GeV electrons in a 04 G field The existence of these electrons, however, is unlikely in that spacecraft observations at 1 AU do not confirm their presence
19 citations
TL;DR: The 7 March, 1970 total solar eclipse was observed at wavelengths of 3.2 and 8.3 mm as mentioned in this paper, where the object was to use the knife edge of the Moon as it passed across the Sun to improve angular resolution on the Sun.
Abstract: The 7 March, 1970 total solar eclipse was observed at wavelengths of 3.2 and 8.3 mm; the object being to use the knife edge of the Moon as it passed across the Sun to improve angular resolution on the Sun. This in turn would provide a radial brightness distribution of the Sun with an angular resolution of a few seconds of arc. Excellent eclipse curves were obtained at 3 mm; however, some external interference marred the 8 mm record near totality. The 8 mm brightness distribution is subject to some uncertainty, but tends to show limb brightening. The 3 mm brightness distribution shows a well defined complex limb brightening within about 1 arc min of the optical limb. The maximum brightening is approximately 30% above the average disc temperature.
TL;DR: Measurements of the zenith sky intensity and spectral distribution during the solar eclipse of 12 November 1966 at Bage, Brazil, and on an aircraft over the Atlantic are reported to define the intensities and changes in spectral distribution and to discuss the dependence of these on such factors as height and terrain.
Abstract: Measurements of the zenith sky intensity and spectral distribution during the solar eclipse of 12 November 1966 at Bage, Brazil, and on an aircraft over the Atlantic are reported. These, together with measurements reported elsewhere from Santa Ines, Peru, and Quehua, Bolivia, are used to define the intensities and changes in spectral distribution during totality and to discuss the dependence of these on such factors as height and terrain.
TL;DR: In this paper, the integrated intensities of Fexiv λ5303, Fex λ6374, and the continuum were measured on the spectrograms as a function of height above the Sun's limb.
Abstract: Spectrographic observations of the flash spectrum were made by the Kwasan Observatory at the total solar eclipse on 7 March, 1970. The integrated intensities of Fexiv λ5303, Fex λ6374, and the continuum were measured on the spectrograms as a function of height above the Sun's limb. It was found that a large amount of emission in the coronal lines originates in the interspicular regions of the chromosphere. Analysis of the data yielded that the interspicular regions consist of coronal material of T
e = 1.6 × 106–1.2 × 106 and log N
e = 8.5–9.5, and that a decrease in T
e and an increase in N
e occur with decreasing height.
TL;DR: In this article, both airborne and ground measurements of the atmospheric potential gradient were made during the total solar eclipse of 7 March 1970 at Norfolk, Virginia, and the airborne measurements suggest possible enhancement and increased variability of the potential gradient during the central portion of the eclipse.
TL;DR: Observations of the zenith sky brightness around totality at 5580 A and 6300 A during the eclipse of 12 November 1966 are reported.
Abstract: This paper reports observations of the zenith sky brightness around totality at 5580 A and 6300 A during the eclipse of 12 November 1966. The observations were carried out at Santa Ines, Huancavelica, Peru, using interference filter photometers. The color change and the variation of the sky brightness at zenith were determined and are presented.
TL;DR: In this paper, the effect of solar eclipses on the geomagnetic field has been summarized by Matsushita1 and Kato3. But the effect to be described here is somewhat different in that the eclipse occurred during a magnetically disturbed time and the effect could only be isolated by comparing magnetic records at an eclipsed station with simultaneous records at other stations situated outside the region of total eclipse.
Abstract: THE effects of solar eclipses on the geomagnetic field have been summarized by Matsushita1. On quiet days clear changes in the geomagnetic field were seen superimposed on the Sq variation by Egedal and Ambolt2 and by Kato3. The effect to be described here is somewhat different in that the eclipse occurred during a magnetically disturbed time and the effect could only be isolated by comparing magnetic records at an eclipsed station with simultaneous records at other stations situated outside the region of total eclipse. In the present study four stations situated on a line approximately at right angles to the path of totality were specially equipped with geomagnetic variographs (Table 1).
TL;DR: In this article, the slitless flash spectrum near the D3 helium line was observed in Yurgamysh at the total solar eclipse of September 22, 1968, with a height resolution of 44 km within the height interval between −3400 and +1700 km above the limb.
Abstract: Cinematographic observations of the slitless flash spectrum near the D3 helium line were performed in Yurgamysh at the total solar eclipse of September 22, 1968. The intensity distribution of the D3 line was obtained with a height resolution of 44 km within the height interval between −3400 and +1700 km above the limb. The absorption line D3 on the disk near the limb was discovered.
TL;DR: Ionospheric E-region observations from Boulder (40.0 N, 105.3 W), Grand Bahama (26.6 N, 78.2 W), Mexico City (19.3 N, 99.6 W), and Wallops Island (37.9 N, 75.5 W) during the total solar eclipse of 7 March, 1970 are used for reconstructing the distribution of the ionizing XUV radiation over the solar disk as mentioned in this paper.
Abstract: Ionospheric E-region observations from Boulder (40.0 N, 105.3 W), Grand Bahama (26.6 N, 78.2 W), Mexico City (19.3 N, 99.2 W), Vandenberg (35.6 N, 120.6 W), and Wallops Island (37.9 N, 75.5 W) during the total solar eclipse of 7 March, 1970 are used for reconstructing the distribution of the ionizing XUV radiation over the solar disk. The derived solar image compares reasonably well with the EUV and X-ray pictures of the Sun obtained from rockets.
TL;DR: In this paper, an estimated flux spectrum of the undisturbed radio Sun for 7 March, 1970 is given and compared to the spectrum for the solar minimum of 1964. But the authors do not consider the effect of the partial solar eclipse on the spectrum.
Abstract: Measurements were made of the 7 March, 1970 solar eclipse by the AFCRL Sagamore Hill Radio Observatory in Hamilton, Massachusetts, on the wavelengths of 0.86, 1.95, 3.4, 6.0, 11.1, 21.2, 49.5, and 122.5 cm. Near-total obscuration (m=0.96) occurred at eclipse maximum. Source flux spectra for the intense sources located in McMath plages 10 618(SE), 10617(NE), and 10 607(NW) show gyro-resonance spectral peaking, whereas the less intense bremsstrahlung emission is observed for the weaker sources in plages 10 614 and 10 619. Associated one-dimensional source sizes for these regions vary from 0.8 arc min (at 3.4 cm) to 5.4 arc min (at 49.5 cm); with sizes at a particular wavelength increasing with intensity of the source. An estimated flux spectrum of the undisturbed radio Sun for 7 March, 1970 is given and compared to the spectrum for the solar minimum of 1964. In plage 10 607 a weak halo emission was isolated from the intense emission from the central source over the spot. The measure of emission \(\overline N ^2 L\) from the halo above plage 10 607 was calculated to be ≈ 7 × 1027 electron2/cm5.
TL;DR: The relative spectral intensity of the zenith sky was measured with an optical scanning spectrometer at Nantucket Island, Massachusetts, during the total solar eclipse of 7 March 1970 and shows a blue color shift consistent with rayleigh scattering.
Abstract: The relative spectral intensity of the zenith sky was measured with an optical scanning spectrometer at Nantucket Island, Massachusetts, during the total solar eclipse of 7 March 1970. The spectral ratios I(5100 A)/I(4300 A) and I(5900 A)/I(5100 A) at Nantucket remained unchanged for 96% or less obscuration of the sun by the moon. The results are compared with other recent relative spectral intensity measurements made during total solar eclipses. Comparison with other eclipse measurements for solar elevation angle at totality less than 45° shows a blue color shift consistent with rayleigh scattering. Eclipses with solar elevation angles at totality greater than 45° do not show consistent color shifts. This inconsistency may be due to difficulty in establishing a suitable reference spectrum for comparison with the spectral distribution of the zenith sky at totality. Selection of a suitable reference spectrum is discussed.
TL;DR: In this paper, an error analysis of more than 1,100 single measurements taken in the afternoon of March 7 (after the eclipse had finished) was carried out, each of which is averaged over twenty-eight single digitized data points taken within four seconds at intervals of three minutes.
Abstract: IT has been predicted that the supersonic movement of the Moon's shadow during a solar eclipse will generate internal gravity waves in the atmosphere1. The bow wave so produced by the Moon's shadow will be manifested by travelling ionospheric disturbances (TIDs). During the March 7 eclipse last year some of the observations at Fort Monmouth, NJ, were devoted to TID observations using measurements of the integrated electron content of the atmosphere, obtained from the polarization of the beacon signal from the ATS-3 satellite at 137.35 MHz. Detection of the predicted motions, by variations in the electron content, depends on achieving sufficient precision in relation to an unknown effect. We therefore carried out an error analysis from more than 1,100 single measurements taken in the afternoon of March 7 (after the eclipse had finished. We found a maximum error of ±5.5 polarization degrees inherent in our new automatic system for the data points in Fig. 1, each of which is averaged over twenty-eight single digitized data points taken within four seconds at intervals of three minutes. This averaging is necessary and compensates for the spin effect on polarization. The same maximum error was observed experimentally when the fluctuations of electron content were studied during ionospherically quiet days. The data of Fig. 1 were obtained using an effective geomagnetic component of constant value, neglecting the unknown variations of this factor. The data were analysed for undulations by taking the differences between actual data and their running mean taken over nine data points, over twenty-seven minutes, in other words. The maximum error for these differences is then ±11 polarization degrees. For reasons of improved reliability, we assumed a maximum error of ±15 degrees or ±3.5×1011 electrons cm−2 for the variations in content deduced during the eclipse (Fig. 2).
TL;DR: In this paper, it was shown that less than 5% of the solar disc power can be contained in any limb brightening of the Sun during the partial solar eclipse of February 25th 1971.
Abstract: Observations at 9 mm wavelength of the partial solar eclipse of February 25th 1971 were made to investigate possible limb brightening of the Sun. The results obtained show that less than 5% of the solar disc power can be contained in any such brightening.
TL;DR: The results of these analyses indicate that there were no significant changes in the orientation of the major axis of the H-D ellipse during the period of the eclipse as discussed by the authors.
Abstract: Three-axis (H, D, Z) measurements of the earth's magnetic field were made at Crawford Hill, New Jersey (∼97% visual obscuration), during the March 7, 1970, solar eclipse. Any hope of detecting an eclipse-associated ionospheric effect by observing a decrease in H or an over-all change in D was eliminated by the occurrence of a disturbed geomagnetic period. Dynamic power spectral analysis was performed on 13 magnetic field pulsations observed in the period range 0.85–6.0 min prior to and during the eclipse. The results of these analyses indicate that there were no significant changes in the orientation of the major axis of the H-D ellipse during the period of the eclipse. This lack of a consistent change would appear to be compatible with the small E layer ionization changes measured during the eclipse period.
TL;DR: In this paper, the spectrum of the solar corona obtained during the eclipse of 7 March, 1970 has been studied from the analysis of the line halfwidths and it is concluded that the emission of coronal lines of various groups arises in different volumes of the corona.
Abstract: The spectrum of the solar corona obtained during the eclipse of 7 March, 1970 has been studied From the analysis of the line halfwidths it is concluded that the emission of coronal lines of various groups arises in different volumes of the corona The lines λ5303 and λ4231 are analyzed in detail and by the use of the equations of excitation and ionization balance The distribution of electron temperature T
e and density n
e vs height in the solar corona has been found The usually adopted n
e and T
e are noticeably less than those values obtained in present analysis This discrepancy may be due to the fact that the considered area of the corona seems to be in an unusual condition
TL;DR: The magnetic field in the outer corona and in interplanetary space has been calculated from the photospheric magnetic fields measured around the time of the 7 March, 1970 eclipse as discussed by the authors.
Abstract: The magnetic field in the outer corona and in interplanetary space has been calculated from the photospheric magnetic fields measured around the time of the 7 March, 1970 eclipse The field-line maps are compared with eclipse photographs showing coronal structures out to about 12 r⊙ The projected field lines as well as the observed streamers appear straight This is caused by the rapid expansion of the outer corona and is not an indication of corotation The calculations show that the angular velocity of the coronal plasma decreases rapidly with distance
TL;DR: In this article, the authors performed measurements at wavelength 1.18 cm during the 1969 partial solar eclipse and observed a high coronal contribution to the emission at this wavelength, but no significant limb-brightening was detected.
Abstract: Measurements performed at wavelength 1.18 cm during the September, 11, 1969, partial solar eclipse are described. No significant limb-brightening was detected. However, a high coronal contribution to the emission at this wavelength was observed. Separation between the emission from the center of a unipolar spot of diameter ≈ 1/2 to 1 arc min and its plage region of diameter ≈ 3 to 4 arc min was possible.
01 Jun 1971
TL;DR: Conjugate photoelectrons existence from rocket measurements during total solar eclipse of 7 March 1970 as discussed by the authors were found to exist from satellite measurements during the eclipse. But they did not exist during the launch of the rocket.
Abstract: Conjugate photoelectrons existence from rocket measurements during total solar eclipse of 7 March 1970
TL;DR: The visual work done at the 1963 and 1966 eclipses is reviewed and a screen of this type was used by two of us at the eclipse of November 12, 1966, in Rio Grande do Sul, Brazil.
Abstract: JUST before and after the total phase of a solar eclipse, faint light and dark bands, resembling interference or diffraction fringes, move across the surface of the Earth These “shadow bands” were first reported as early as 1842 (ref 1) Work by Feldman2 indicated that the orientation of the bands was related to the shape of the shadow on the surface of the Earth, but many of the data were difficult to interpret Paulton3 has described a screen with which visual observations can be made with some degree of accuracy and consistency, and a screen of this type was used by two of us (M E H and R D B) at the eclipse of November 12, 1966, in Rio Grande do Sul, Brazil4 Paulton5 has reviewed the visual work done at the 1963 and 1966 eclipses
TL;DR: In this paper, a comprehensive version of the steady state ionospheric continuity equation is solved for theoretical comparison of two different partial solar eclipses, each for two different stations, and it is shown that it is not possible to reproduce the ionosphere eclipse effects satisfactorily using solar EUV radiation as the only source of ionization.