Solar Eclipse Of August Research Articles

Techniques for Payload Stabilization for Improved Photography During Stratospheric Balloon Flights

Payload-box rotation and swing are perennial challenges to achieving high-quality photography (typically videography) during weather-balloon flights to “near-space” (AKA the stratosphere). Continuous camera motion can lead to blurred still photos, nearly-impossible-to-watch video footage, and precludes time-exposure photography required for most astronomical imaging even though altitudes are reached where the daytime sky appears black. Apparently-random payload rotation, persisting even at altitude, can often exceed servo rotation rates and frustrate attempts to do active camera pointing. Here we discuss mostly-passive payload stabilization strategies we, and our collaborators, have used to mitigate and dampen both swing and rotation of suspended payloads on high-altitude balloon missions, primarily on ascent. In particular, we stress the importance of avoiding single “main” lines and of firmly coupling the payload stack to, as opposed to intentionally trying to decouple (rotationally) from, the neck of the balloon. We discuss consequences these strategies have on stack weight and also on the location of the parachute, sometimes displacing it from its normal location hanging between the neck of the balloon and the payload stack. We expect these payload stabilization techniques will be of particular interest to balloonists planning to photograph the total solar eclipse of August 2017.

Ionospheric Response to the Total Solar Eclipse of August 21, 2017, and Its Impact on GNSS Positioning

AbstractThe solar eclipse on August 21, 2017, passed through North America and considerably affected the electron density in the ionosphere. By taking advantage of a global navigation satellite sys...

Foraging and homing behavior of honey bees (Apis mellifera) during a total solar eclipse.

Exceptional natural phenomena, such as those that occur during a total solar eclipse, provide unique opportunities to study animal behavior outside the naturally evolved context, which can be informative in more general terms. Circumstantial descriptions of abnormal animal behavior during solar eclipses abound, although scientific studies conducted during an eclipse are relatively rare due to inherent logistical difficulties. Here, honey bee foraging and homing behavior were studied during the total solar eclipse of August 21, 2017. In the first experiment, we studied foraging behavior of honey bees during the progression of the solar eclipse and found that the foraging activity drastically decreased but did not completely cease during the totality of the eclipse, in contrast to previous reports of complete cessation. The data indicate that the level of ambient light can largely overrule the internal circadian rhythm of foraging honey bees. Furthermore, colonies with a higher need for foraging decreased their foraging activity less than satiated colonies, consistent with the hypothesis that individual foraging decisions may be influenced by colony state, which affects cost-benefit analyses. In a second experiment, the temporal dynamics of homing of released workers and drones was compared in periods before, during, and after the solar eclipse. During the totality of the eclipse, very few bees arrived back at their hive, while homing before the total eclipse was accelerated, particularly in drones. The results suggest that, while the homing abilities of honey bees are not compromised until the sun is completely eclipsed, they may still interpret the diminishing light as an indicator of deteriorating flight conditions. Our unique study provides some insight into the control of honey bee foraging behavior when external cues and internal circadian rhythms are at odds, lent support to the notion that food deprivation can lead to riskier foraging, and indicated that homing in honey bees is possible even with very small amounts of sunlight.

ЭФФЕКТЫ СОЛНЕЧНОГО ЗАТМЕНИЯ 20 МАРТА 2015 Г. В ИОНОСФЕРЕ НАД ЕВРОПОЙ: РЕЗУЛЬТАТЫ ИОНОЗОНДОВЫХ НАБЛЮДЕНИЙ

ЭФФЕКТЫ СОЛНЕЧНОГО ЗАТМЕНИЯ 20 МАРТА 2015 Г. В ИОНОСФЕРЕ НАД ЕВРОПОЙ: РЕЗУЛЬТАТЫ ИОНОЗОНДОВЫХ НАБЛЮДЕНИЙ

ТЕПЛОВЫЕ И ДИНАМИЧЕСКИЕ ПРОЦЕССЫ В ИОНОСФЕРЕ ВО ВРЕМЯ ЧАСТНОГО ЗАТМЕНИЯ СОЛНЦА 20 МАРТА 2015 г. НАД ХАРЬКОВОМ. РЕЗУЛЬТАТЫ РАСЧЕТОВ

ТЕПЛОВЫЕ И ДИНАМИЧЕСКИЕ ПРОЦЕССЫ В ИОНОСФЕРЕ ВО ВРЕМЯ ЧАСТНОГО ЗАТМЕНИЯ СОЛНЦА 20 МАРТА 2015 г. НАД ХАРЬКОВОМ. РЕЗУЛЬТАТЫ РАСЧЕТОВ

Solar eclipse of August 1, 2008, above Kharkov: 2. Observation results of wave disturbances in the ionosphere

Quasi-periodic variations in the power of incoherent scattered signals, caused by wave disturbances of the electron concentration in the ionosphere, are analyzed for the day of a partial solar eclipse and for a background day. The windowed and adaptive Fourier transforms and the wavelet transform are used for spectral analysis. The spectral parameters of the wave disturbances at altitudes of 100–500 km in the 10–120 min period range differed significantly on the day of the solar eclipse and on the background day. Variations in the spectrum began near the onset of the phase of maximum disk occultation and continued no less than 2 h. The amplitude of time variations N was 2 × 109–4 × 1010 m−3, and the relative amplitude was 0.10–0.15. Wave disturbances have been compared for five solar eclipses; the comparison shows a noticeable variation in the spectrum of the wave disturbances during these events.

Solar eclipse of August 1, 2008, above Kharkov: 1. Results of incoherent scatter observations

The observation results of the effects in the geospace plasma during a partially (magnitude ∼0.42) solar eclipse are presented. The experimental data were obtained with an incoherent scatter radar of the Institute of the Ionosphere (near Kharkov). During the eclipse, the density at the F2 layer maximum decreased by 32%, the foF2 critical frequency decreased by 17.5%, and the altitude of the F2 layer maximum increased insignificantly. At altitudes of 290–680 km, the electron density decreased by ∼25%. During the eclipse, the electron and ion temperature decreased by 70–180 and 0–140 K, respectively, at altitudes of 190–490 km. Near the eclipse main phase, the plasma velocity vertical component decreased by 10–45 m/s at altitudes of 200–470 km, respectively. At the time of the eclipse main phase, the hydrogen ion fractional density increased by 50% as compared to the reference day at altitudes of 450–650 km.

Dynamic processes in the near-ground atmosphere during the solar eclipse of August 1, 2008

The optical observations and dynamics analysis of the effects in the near-ground atmosphere accompanying a partial (about 0.42 magnitude) solar eclipse (SE) near Kharkov, Ukraine, on August 1, 2008, are described in comparison with the effects of the partial eclipses on August 11, 1999, and October 3, 2005. All three SEs occurred around midday. The SE of August 1 was accompanied by a 2.0° decrease in the near-ground atmospheric temperature. It is found that, when the obscuration function was maximum (0.31), the standard deviation in the solar-limb displacement decreased by 0.30″. The measured fluctuations of the jitter level of the solar limb edge were used to estimate the parameters of the near-ground atmosphere and turbulence.

Simultaneous observations of the natural electromagnetic emission in the ELF-VLF range at Kamchatka and in Yakutia during the solar eclipse of August 1, 2008

The effect of the solar eclipse that occurred on August 1, 2008, on the level of the natural electro-magnetic emission signals in the ELF-VLF range, simultaneously observed at Kamchatka and in Yakutsk, and the variations in the amplitude and phase of signals from the VLF radiostations, registered in Yakutsk, has been considered. The VLF radiostations in Krasnodar, Novosibirsk, and Khabarovsk successively emitted signals at frequencies of 11 905, 12 649, and 14 880 Hz. Based on the observations of the signals from these radiostations, it has been established that the signal amplitudes and phases increased by 3–5% and 30°–45° when the signals crossed the lunar shadow region. The synchronous registration of the ELF-VLF noise emission indicated that a bay-like increase and the following decrease in the emission to the background level was observed at both receiving points during the eclipse from ∼1000 to 1130 UT. This effect was registered at frequencies of 0.6–5.6 kHz in Yakutsk and at lower (30–200 Hz) and higher (2.5–11 kHz) frequencies at Kamchatka. In this case the noise emission intensity maximum was observed when the lunar shadow maximally approached the registration point. At higher frequencies, the emission maximum was observed simultaneously at both points (at 1100 UT) but with a delay relative to the maximum at lower frequencies. The possible causes of the appearance of the solar eclipse effects in the natural ELF-VLF emission are considered.

Feature of the multifractal structure of small-scale ionospheric turbulence during the solar eclipse of August 1, 2008

Using the method of radio sounding of the mid-latitude ionosphere by the satellite signals, we study the multifractal structure of small-scale ionospheric turbulence during a solar eclipse. The measured multipower and generalized multifractal spectra of small-scale ionospheric turbulence at the initial and closing stages of the eclipse turn out to be almost identical on the space radio paths with different orientations. This is indicative of a sufficiently high stability of the nonuniform spatio-temporal distribution of small-scale fluctuations of the ionospheric electron number density under conditions of geophysical disturbances due to global physical processes in the ionospheric plasma during a solar eclipse.

Effect of the August 11, 1999 total solar eclipse on geomagnetic pulsations

The total solar eclipse of August 11, 1999 offered a unique opportunity for the study of its geomagnetic effect — more specifically, of its effect on geomagnetic (Pc3) pulsations, as it swept through Europes many observatories, and additional temporary stations have also been established by Japanese, German and Hungarian groups. The present paper starts with an analysis of the ionospheric-interplanetary background. In the interplanetary medium, no indication was found which could result in any extraordinary event in pulsation activity. The both horizontally and vertically widespread ionospheric effect (electron density decrease) explains a change of the polarisation angle by about ten degrees in the local field line resonance (FLR) band. However, the most significant solar eclipse effect was identified as dramatic clockwise rotation (up to 70 degrees) of the polarisation ellipse of Pc3, Pc4 and Pc5 pulsations. Pulsation data exhibit a strong amplitude decrease (roughly by a factor of two) in and around the totality spot of the eclipse. The decrease is most significant at the local field line resonance (FLR) period. In the actual case, the FLR decrease swept over Europe with a speed being similar to the speed of the dark spot. We suppose that the FLR mechanism was disturbed by the change of particle distribution along the field lines ending in the dark zone due to upward propagation of the electron density decrease caused by the lack of ionising solar radiation in the E-layer of the ionosphere. Thus, the FLR mechanism can be disturbed both from outside, by a sudden change of the interplanetary magnetic field (Verő et al. 1998) and from inside, by a change of the particle density/distribution along the actual field line.

Disturbances in the ionosphere and atmosphere caused by the solar eclipse of August 11, 1999

Results of comparing ionospheric radio noise at wavelength of 2 m at midlatitudes to the data of the ionospheric vertical sounding during the partial phase of the solar eclipse of August 11, 1999, are presented. Disturbances in the ionospheric layers, radio noise of the ionospheric plasma, and variations and fluctuations in the atmospheric pressure at the Earth surface during the eclipse are considered. The parameters of the Lamb wave, which propagated with velocity of 300 m/s from the region of the total phase of the eclipse are determined. The Lamb wave characteristics in the summer midlatitude and auroral ionosphere have been compared.

In pursuit of the ineffable: how television found the eclipse but lost the plot

Conventionally, live television constructs the event by bringing together many spatially dispersed occurrences and articulating them through the electronic mediation of the broadcast. This article discusses one live event - the total solar eclipse in August 1999 - for which this `complex connectivity' at the heart of the event was to prove deeply problematic. In the case of the eclipse, what was at stake was not a set of different but related occurrences but rather the same occurrence - the singular and liminal moment of totality - as it occurred and re-occurred in different places. Caught up in a set of contradictory imperatives - to produce the moment, to deliver to the viewer a sense of `being there' but also to deliver the everywhere of the occasion - television mislaid the event.

Development of meteorological parameters and total ozone during the total solar eclipse of August 11, 1999

During the total eclipse of August 11, 1999 frequent showers occurred due to a unstable stratification of the air mass. At different observation sites, meteorological effects from the eclipse (99.4% coverage at Hohenpeissenberg) and from showers were superimposed making it partly difficult to unambiguously interpret the observations. The weather radar at Hohenpeissenberg observatory provided a general overview of the distribution of clouds and precipitation in this area (200 km diameter). From the Garching site in the zone of totality (100%) temperature and wind data taken on a 50 m mast were evaluated. By selecting periods with relatively low cloud cover it was possible to approximately follow the development of the vertical temperature and wind profiles during the eclipse. The minimum temperature at Hohenpeissenberg (about 450 m above the altitude of Garching) during the eclipse was comparable to that during the previous night, the corresponding value measured at Garching remained about 2 K above the minimum observed during clear sky conditions in the previous night. Showers before, during or after the eclipse may have induced vertical exchange of air parcels. Temperatures during a shower change towards the same direction at all altitudes, thus no inversion forms. Additionally, air parcels with relatively lower concentrations of trace constituents were transported down from aloft for time periods of 10-15 minutes. These mixing processes significantly determined the temporal variations of various trace substances measured during the eclipse. Total ozone measurements at Hohenpeissenberg were performed with both DOBSON and BREWER spectrophotometers and at another site within the zone of totality by using a portable Microtops II filter instrument. Different results were obtained for both sites. These differences can be to a large extend, but not exclusively, attributed to eclipse induced shifts (limb darkening and straylight effects in the atmosphere) in the wavelength pairs used to calculate total ozone. However, there also appeared to be real fluctuations in total ozone during the reemerging phase of the sun which may be related to eclipse induced gravity waves.

The Influence of a solar eclipse on temperature and wind in the Upper-Rhine Valley - A numerical case study

The effects on temperature and wind caused by the solar eclipse of August 11, 1999 in the south western part of Germany were simulated. While during the real event clouds and precipitation were present in most of the model domain cloud free conditions are assumed for the simulation. A temperature decrease of up to 7 K was simulated during the eclipse event close to the surface. Thermal stability changes from unstable to stable conditions and the temperature gradient reaches values which are comparable to those normally found after sunset. Temperature keeps about 1 K lower after the eclipse event during the rest of the day. Boundary layer height shortly after the eclipse event differs by several hundred meters. The effects on wind speed are rather small with the exception of the slopes of the mountains and in the vicinity of Lake Constance.

Inertially stabilized pointing control system

A pointing control system, combining passive inertial stabilization with active control, is presented. Such systems can direct an apparatus towards a fixed or slow moving target from a moving vehicle whose motion is almost rectilinear. The system was initially conceived to study the total solar eclipse in August 1999 in Romania. The passive inertial stabilization method consists of suspending a large mass by means of very low friction bearings. Consequently, a good static and dynamic equilibration is required. If the position information used by the control system is obtained by processing the image of the target, the large time delay involved makes the control synthesis rather difficult. In this paper, two control synthesis approaches, both providing the required tracking precision, and a comparison between the two corresponding control algorithms are presented.

Correction to the field of view for the high altitude observatory mark III K-coronameter

The field of view widely in use for representation of the coronal data collected with the Mark III K-coronameter at Mauna Loa is incorrect. Analysis of the observations of a partial solar eclipse in August 1980 and of observations of high eruptive prominences seen both with the K-coronameter and the occulted Hα chromospheric telescope at Mauna Loa indicate that the field of view actually begins 0.09 R⊙ higher than thought; the pixel-to-pixel separation is as originally published. We describe the analysis which leads to the description of the image scale and discuss both the qualitative and quantitative effects of this new information on published results.

Observations on the Behavior of Animals during the Total Solar Eclipse of August 31, 1932

Observations on the Behavior of Animals during the Total Solar Eclipse of August 31, 1932

PRELIMINARY REPORT OF THE EXPEDITIONS FOR OBSERVING THE TOTAL SOLAR ECLIPSES OF AUGUST 31, 1932, AND FEBRUARY 14, 1934

PRELIMINARY REPORT OF THE EXPEDITIONS FOR OBSERVING THE TOTAL SOLAR ECLIPSES OF AUGUST 31, 1932, AND FEBRUARY 14, 1934

Some Observations of the Sky Polarization During the Total Solar Eclipses of August 31, 1932 and February 14, 1934

Some Observations of the Sky Polarization During the Total Solar Eclipses of August 31, 1932 and February 14, 1934