scholarly journals THE COMPLEX OF ANCIENT OBSERVATORIES ON THE TABLE MOUNTAIN IN INGUSHETIA

2021 ◽  
pp. 10-21
Author(s):  
B. Rezvantsev
Keyword(s):  
Annual Cycle ◽  
Computer Programs ◽  
The Sun ◽  
Solar Cycles ◽  
The Caucasus ◽  
Astronomical Observations ◽  
Table Mountain ◽  
Instrumental Observations

The proximity of the three ancient sanctuaries to each other on the flat top of the Table Mountain against the background of the sacred peaks of Kazbek and Tsey-Loam, the opportunity to observe the sunrises and sunsets in the highlands of the Caucasus, cosmogonic myths, all this gave an assumption about the astronomical functions of these sanctuaries. The purpose of the study was to prove that these ancient sanctuaries were used by the priests to determine the key moments in the annual cycle of the Sun and were a calendar. This is proved by using special computer programs and calculators that determine the azimuth and altitude of the Sun; instrumental observations and measurements on the ground. It is established that the shrines of Myat-Seli and Myater-Dyal on Table Mountain in Ingushetia are a complex of medieval solar near-horizon observatories. And it is hypothesized that these sanctuaries were built on the site from which solar cycles were observed from about the beginning of the 1st millennium BC. This work also provides prerequisites for determining various astronomical observations from sanctuaries and the presence of other ancient observatories in the Caucasus. A method has been developed for searching for prehistoric solar, lunar and stellar near-horizon observatories.

scholarly journals A review of the SCOSTEP’s 5-year scientific program VarSITI—Variability of the Sun and Its Terrestrial Impact

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kazuo Shiokawa ◽  
Katya Georgieva
Keyword(s):  
Solar Wind ◽  
Interplanetary Space ◽  
Solar Wind Plasma ◽  
The Sun ◽  
Scientific Program ◽  
Solar Cycles ◽  
Grand Minimum ◽  
The Earth ◽  
Earth Connection ◽  
Near Future

AbstractThe Sun is a variable active-dynamo star, emitting radiation in all wavelengths and solar-wind plasma to the interplanetary space. The Earth is immersed in this radiation and solar wind, showing various responses in geospace and atmosphere. This Sun–Earth connection variates in time scales from milli-seconds to millennia and beyond. The solar activity, which has a ~11-year periodicity, is gradually declining in recent three solar cycles, suggesting a possibility of a grand minimum in near future. VarSITI—variability of the Sun and its terrestrial impact—was the 5-year program of the scientific committee on solar-terrestrial physics (SCOSTEP) in 2014–2018, focusing on this variability of the Sun and its consequences on the Earth. This paper reviews some background of SCOSTEP and its past programs, achievements of the 5-year VarSITI program, and remaining outstanding questions after VarSITI.

scholarly journals GERBERT OF AURILLAC: ASTRONOMY AND GEOMETRY IN TENTH CENTURY EUROPE

2013 ◽  
Vol 23 ◽  
pp. 467-471 ◽  
Author(s):  
COSTANTINO SIGISMONDI
Keyword(s):  
Rational Approximation ◽  
Equilateral Triangle ◽  
Tenth Century ◽  
The Sun ◽  
Astronomical Observations ◽  
The North ◽  
Celestial Pole ◽  
Gerbert Of Aurillac

Gerbert of Aurillac was the most prominent personality of the tenth century: astronomer, organ builder and music theoretician, mathematician, philosopher, and finally pope with the name of Silvester II (999–1003). Gerbert introduced firstly the arabic numbers in Europe, invented an abacus for speeding the calculations and found a rational approximation for the equilateral triangle area, in the letter to Adelbold here discussed. Gerbert described a semi-sphere to Constantine of Fleury with built-in sighting tubes, used for astronomical observations. The procedure to identify the star nearest to the North celestial pole is very accurate and still in use in the XII century, when Computatrix was the name of Polaris. For didactical purposes the Polaris would have been precise enough and much less time consuming, but here Gerbert was clearly aligning a precise equatorial mount for a fixed instrument for accurate daytime observations. Through the sighting tubes it was possible to detect equinoxes and solstices by observing the Sun in the corresponding days. The horalogium of Magdeburg was probably a big and fixed-mount nocturlabe, always pointing the star near the celestial pole.

The Spread Wings Motif on Armenian Steles: Its Meaning and Parallels in Sasanian Art

2010 ◽  
Vol 14 (2) ◽  
pp. 201-232 ◽  
Author(s):  
Matteo Compareti
Keyword(s):  
Persian Gulf ◽  
Late Antiquity ◽  
Western Coast ◽  
The Sun ◽  
Persian Empire ◽  
The Caucasus ◽  
The Cross ◽  
The Persian Gulf ◽  
Armenian Literature

AbstractThis paper is a study on the so-called “spread wings”—a particular element of the Sasanian art that is attested also in other regions of the Persian Empire in Late Antiquity, including the western coast of the Persian Gulf and the Caucasus. The spread wings can be observed on Sasanian coins above the royal crowns, which are considered specific for every Sasanian sovereign, supporting astronomical elements, like the crescent, star, and, possibly, the sun. The Arabs and the peoples of the Caucasus who adopted Christianity used the spread wings element as a pedestal for the cross. In Armenian literature, there are some connections between those spread wings and glory, so that a kind of pedestal could be considered a device to exalt or glorify the element above it. The floating ribbons attached to Sasanian crowns had possibly the same meaning and were adopted also outside of proper Persia. In the same way, it could be considered correct to identify those luminaries on Sasanian crowns as divine elements connected with the religion of pre-Islamic Persia.

scholarly journals XXI. On the dispersive power of the atmosphere, and its effect on astronomical observations

1815 ◽  
Vol 105 ◽  
pp. 375-383
Keyword(s):  
The Sun ◽  
Astronomical Observations ◽  
Dark Glass ◽  
Dispersive Power

Notwithstanding the pains which astronomers have taken to determine accurately the refraction of mixed light, nothing, I believe, has ever been done towards ascertaining the dispersive power of common air, or comparative degree of refrangibility of the differently coloured rays in their passage through our atmosphere. The importance of such an inquiry, however, must be obvious to every one who duly considers the effect which the different degrees of refrangibility of the variously coloured lights must necessarily produce in the apparent situations of differently coloured objects. Stars of different colours must be differently refracted, and the apparent altitude of the sun must vary according to the colour of the dark glass through which he is viewed.

ESTABLISHING SOLAR ACTIVITY TREND FOR SOLAR CYCLES 21 – 24

2021 ◽  
Vol 44 ◽  
pp. 100-106
Author(s):  
A.K. Singh ◽  
◽  
A. Bhargawa ◽  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Sunspot Number ◽  
Cosmic Ray ◽  
Occurrence Rate ◽  
The Sun ◽  
Solar Cycles ◽  
Lyman Alpha ◽  
Rate Versus ◽  
Alpha Index

Solar-terrestrial environment is manifested primarily by the physical conditions of solar interior, solar atmosphere and eruptive solar plasma. Each parameter gives unique information about the Sun and its activity according to its defined characteristics. Hence the variability of solar parameters is of interest from the point of view of plasma dynamics on the Sun and in the interplanetary space as well as for the solar-terrestrial physics. In this study, we have analysed various solar transients and parameters to establish the recent trends of solar activity during solar cycles 21, 22, 23 and 24. The correlation coefficients of linear regression of F10.7 cm index, Lyman alpha index, Mg II index, cosmic ray intensity, number of M & X class flares and coronal mass ejections (CMEs) occurrence rate versus sunspot number was examined for last four solar cycles. A running cross-correlation method has been used to study the momentary relationship among the above mentioned solar activity parameters. Solar cycle 21 witnessed the highest value of correlation for F10.7 cm index, Lyman alpha index and number of M-class and X-class flares versus sunspot number among all the considered solar cycles which were 0.979, 0.935 and 0.964 respectively. Solar cycle 22 recorded the highest correlation in case of Mg II index, Ap index and CMEs occurrence rate versus sunspot number among all the considered solar cycles (0.964, 0.384 and 0.972 respectively). Solar cycle 23 and 24 did not witness any highest correlation compared to solar cycle 21 and 22. Further the record values (highest value compared to other solar three cycles) of each solar activity parameters for each of the four solar cycles have been studied. Here solar cycle 24 has no record text at all, this simply indicating that this cycle was a weakest cycle compared to the three previous ones. We have concluded that in every domain solar 24 was weaker to its three predecessors.

James Bradley, Sailing on the Thames

Lightspeed ◽  
2019 ◽  
pp. 49-57
Author(s):  
John C. H. Spence
Keyword(s):  
Eighteenth Century ◽  
Experimental Evidence ◽  
The Sun ◽  
Theory Of Relativity ◽  
Speed Of Light ◽  
Astronomical Observations ◽  
The Earth ◽  
Independent Estimate ◽  
The Universe ◽  
At Home

The story of the astronomical observations of James Bradley in the eighteenth century, whose measurements of the small movements of a star throughout the year provided an independent estimate of the speed of the Earth around the Sun relative to the speed of light. His work provided the first experimental evidence in support of Copernicus’s theory that the earth is in motion, and against the idea that it is stationary at the center of the universe. His simple telescope at home, his brilliant idea and perseverance, and his life’s work and influence. The importance of his result for the development of Einstein’s theory of relativity and for theories of the Aether in the following centuries.

scholarly journals Mass loss via solar wind and coronal mass ejections during solar cycles 23 and 24

2019 ◽  
Vol 486 (4) ◽  
pp. 4671-4685 ◽  
Author(s):  
Wageesh Mishra ◽  
Nandita Srivastava ◽  
Yuming Wang ◽  
Zavkiddin Mirtoshev ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Mass Loss ◽  
Sunspot Number ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Occurrence Rate ◽  
The Sun ◽  
Solar Cycles ◽  
X Ray ◽  
X Ray Background

ABSTRACT Similar to the Sun, other stars shed mass and magnetic flux via ubiquitous quasi-steady wind and episodic stellar coronal mass ejections (CMEs). We investigate the mass loss rate via solar wind and CMEs as a function of solar magnetic variability represented in terms of sunspot number and solar X-ray background luminosity. We estimate the contribution of CMEs to the total solar wind mass flux in the ecliptic and beyond, and its variation over different phases of the solar activity cycles. The study exploits the number of sunspots observed, coronagraphic observations of CMEs near the Sun by SOHO/LASCO, in situ observations of the solar wind at 1 AU by WIND, and GOES X-ray flux during solar cycles 23 and 24. We note that the X-ray background luminosity, occurrence rate of CMEs and ICMEs, solar wind mass flux, and associated mass loss rates from the Sun do not decrease as strongly as the sunspot number from the maximum of solar cycle 23 to the next maximum. Our study confirms a true physical increase in CME activity relative to the sunspot number in cycle 24. We show that the CME occurrence rate and associated mass loss rate can be better predicted by X-ray background luminosity than the sunspot number. The solar wind mass loss rate which is an order of magnitude more than the CME mass loss rate shows no obvious dependency on cyclic variation in sunspot number and solar X-ray background luminosity. These results have implications for the study of solar-type stars.

Distribution of LDE flares on the Sun during solar cycles 20 and 21

1989 ◽  
Vol 162 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Atila �zg�� ◽  
Ayten D�zgelen
Keyword(s):  
The Sun ◽  
Solar Cycles

scholarly journals VIII. Astronomical observations. In two letters from M. Francis de Zach, Professor of Mathematics, and Member of the Royal Academies of Sciences at Marseilles, Dijon, and Lyons, to Mr. Tiberius Cavallo, F. R. S

1785 ◽  
Vol 75 ◽  
pp. 137-152
Keyword(s):  
Royal Society ◽  
The Sun ◽  
The Moon ◽  
Vernal Equinox ◽  
Astronomical Observations ◽  
Pendulum Clock ◽  
Jupiter’S Satellites

Sir, I send you the account of the observations on the eclipse of the moon, which I have made together with the rev. Father Le Fevre, Astronomer at Lyons, in the Observatory called au grand Collège ; to which I shall add the observations of the vernal equinox; some observation son Jupiter's satellites, made at Marseilles by M. Saint Jacques de Sylvabelle; and, lastly, a new solution of a problem that occurs in computing the orbits of comets. If you think that these observations do in any way deserve the notice of the Royal Society, I ascertain the going of the pendulum clock, I took several corresponding altitudes of the sun, which you will find in the following table.On the day of the eclipse the sky was very serene, nothing could be finer, and it continued so during the observation.

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