scholarly journals Solar observations by the large pulkovo radio telescope at 3.2-cm wavelength

1959 ◽  
Vol 9 ◽  
pp. 171-173
Author(s):  
V. Ikhsanova
Keyword(s):  
Radio Telescope ◽  
The Sun ◽  
Solar Observations ◽  
Large Pulkovo Radio Telescope

The observations of the sun by the large Pulkovo radio telescope [1] began in 1956 December. In accordance with the antenna dimensions, a fan-beam diagram about one minute of arc in width and one degree in height was expected (at λ = 3.2 cm).

scholarly journals EXPLORATION OF THE SOLAR DECAMETER RADIO EMISSION WITH THE UTR-2 RADIO TELESCOPE

2021 ◽  
Vol 26 (1) ◽  
pp. 74-89
Author(s):  
V. N Melnik ◽  
◽  
A. A. Konovalenko ◽  
V. V. Dorovskyy ◽  
A. Lecacheux ◽  
...  
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Solar Radio Emission ◽  
The Sun ◽  
Type Ii ◽  
Time Frequency ◽  
Type Iii ◽  
Type Iv ◽  
Decameter Radio ◽  
Type Ii Bursts

Purpose: The overview of the scientifi c papers devoted to the study of the solar decameter radio emission with the world’s largest UTR-2 radio telescope (Ukraine) published for the last 50 years. Design/methodology/approach: The study and analysis of the scientifi c papers on both sporadic and quiet (thermal) radiation of the Sun recorded with the UTR-2 radio telescope at the decameter wavelength range. Findings: The most signifi cant observational and theoretical results of the solar radio emission studies obtained at the Institute of Radio Astronomy of the National Academy of Sciences of Ukraine for the last 50 years are given. Conclusions: For the fi rst time, at frequencies below 30 MHz, the Type II bursts, Type IV bursts, S-bursts, drift pairs and spikes have been recorded. The dependences of these bursts parameters on frequency within the frequency band of 9 to 30 MHz were obtained. The models of their generation and propagation were suggested. Moreover, for the fi rst time the fi ne time-frequency structures of the Type III bursts, Type II bursts, Type IV bursts, U- and J-bursts, S-bursts, and drift pairs have been observed due to the high sensitivity and high time-frequency resolutions of the UTR-2 radio telescope. The super-fi ne structure of Type II bursts with a “herringbone” structure was identifi ed, which has never been observed before. New types of bursts were discovered: “caterpillar” bursts, “dog-leg” bursts, Type III bursts with decay, Type III bursts with changing drift rate sign, Type III-like bursts, Jb- and Ub-bursts, etc. An interpretation of the unusually high drift rates and drift rates with alternating signs of the Type III-like bursts was suggested. Based on the dependence of spike durations on frequency, the coronal plasma temperature profi le at the heliocentric heights of 1.5–3RS was determined. Usage of the heliographic and interferometric methods gave the possibility to start studies of the spatial characteristics – sizes and locations of the bursts emission sources. Thus, it was shown that at the decameter band, the Type III burst durations were defi ned by the emission source linear sizes, whereas the spike durations were governed by the collision times in the source plasma. It was experimentally proved that the effective brightness temperatures of the sources of solar sporadic radio emission at the decameter band may reach values of 1014–1015 K. In addition, it was found that the radii of the quiet Sun at frequencies 20 and 25 MHz are close to the distances from the Sun at which the local plasma frequency is equal to the corresponding observed frequency of radio emission in the Baumbach–Allen model. Key words: UTR-2; Sun; decameter radio emission; radio bursts; corona

scholarly journals Synoptic solar observations of the Solar Flare Telescope focusing on space weather

2020 ◽  
Vol 10 ◽  
pp. 41 ◽  
Author(s):  
Yoichiro Hanaoka ◽  
Takashi Sakurai ◽  
Ken’ichi Otsuji ◽  
Isao Suzuki ◽  
Satoshi Morita
Keyword(s):  
Magnetic Field ◽  
Solar Flare ◽  
Space Weather ◽  
Solar Observation ◽  
The Sun ◽  
Solar Observations ◽  
Solar Filaments ◽  
Field Information ◽  
Activity Cycles ◽  
Synoptic Observations

The solar group at the National Astronomical Observatory of Japan is conducting synoptic solar observation with the Solar Flare Telescope. While it is a part of a long-term solar monitoring, contributing to the study of solar dynamo governing solar activity cycles, it is also an attempt at contributing to space weather research. The observations include imaging with filters for Hα, Ca K, G-band, and continuum, and spectropolarimetry at the wavelength bands including the He I 1083.0 nm/Si I 1082.7 nm and the Fe I 1564.8 nm lines. Data for the brightness, Doppler signal, and magnetic field information of the photosphere and the chromosphere are obtained. In addition to monitoring dynamic phenomena like flares and filament eruptions, we can track the evolution of the magnetic fields that drive them on the basis of these data. Furthermore, the magnetic field in solar filaments, which develops into a part of the interplanetary magnetic cloud after their eruption and occasionally hits the Earth, can be inferred in its pre-eruption configuration. Such observations beyond mere classical monitoring of the Sun will hereafter become crucially important from the viewpoint of the prediction of space weather phenomena. The current synoptic observations with the Solar Flare Telescope is considered to be a pioneering one for future synoptic observations of the Sun with advanced instruments.

High Resolution Solar Observations at Three Frequencies: 1424 MHz, 696 MHz and 408 MHz

1967 ◽  
Vol 1 (2) ◽  
pp. 45-46
Author(s):  
D. G. Cole ◽  
R. F. Mullaly ◽  
A. Watkinson
Keyword(s):  
High Resolution ◽  
Radio Emission ◽  
Solar Radio ◽  
Solar Radio Emission ◽  
The Sun ◽  
Physical Mechanisms ◽  
Solar Observations ◽  
Source Structure ◽  
East West

During the period 1966 July 12 to August 5 observations were made of the Sun at three radio observatories. The instruments used were the east-west arm of the Mills cross at Molonglo (408 MHz) and the Christiansen cross at Fleurs (696 MHz and 1424 MHz). The aim of these observations was to study the discrete sources of the slowly varying component of solar radio emission, while activity was comparatively quiet. The three frequencies enabled the variation of source structure with height of solar atmosphere to be studied. It has been pointed out by Swarup et al., and Christiansen et al. that the determination of the frequency dependence of these discrete sources is important for defining the physical mechanisms causing the radio emission.

From E-Group to Funerary Pyramid: Mortuary Cults and Ancestor Veneration in the Maya Centre of Nakum, Petén, Guatemala

2017 ◽  
Vol 27 (3) ◽  
pp. 451-478 ◽  
Author(s):  
Jarosław Źrałka ◽  
Wiesław Koszkul ◽  
Bernard Hermes ◽  
Juan Luis Velásquez ◽  
Varinia Matute ◽  
...  
Keyword(s):  
Complex Structure ◽  
Classic Period ◽  
The Sun ◽  
Social Changes ◽  
Ancestor Veneration ◽  
Solar Observations ◽  
Preclassic Period ◽  
The Temple

Recent investigations at the Maya centre of Nakum (in Guatemala) enabled the study of the evolution of an interesting complex of buildings that started as the so-called E-Group, built during the Preclassic period (c. 600–300 bc). It was used for solar observations and rituals commemorating agricultural and calendrical cycles. During the Classic period (ad 250–800), the major building of the complex (Structure X) was converted into a large pyramidal temple where several burials, including at least one royal tomb, were placed. We were also able to document evidence of mortuary cults conducted by the Maya in the temple building situated above the burials. The architectural conversion documented in Structure X may reflect important religious and social changes: a transformation from the place where the Sun was observed and worshipped to the place where deceased and deified kings were apotheosized as the Sun Deity during the Classic. Thus the Maya transformed Structure X into one of the most sacred loci at Nakum by imbuing it with a complex solar and underworld symbolism and associating it with the cult of deified ancestors.

scholarly journals New Observational Aspects

1990 ◽  
Vol 138 ◽  
pp. 469-487
Author(s):  
Oddbj⊘rn Engvold
Keyword(s):  
High Resolution ◽  
Canary Islands ◽  
Solar Physics ◽  
High Resolution Imaging ◽  
The Sun ◽  
Image Stabilization ◽  
Structure And Dynamics ◽  
Solar Observations ◽  
Methods And Techniques ◽  
Resolution Imaging

The requirements and conditions for high resolution imaging and polarimetry of the Sun are reviewed. Various methods and techniques are discussed for image stabilization and sharpening in solar observations. The new solar facilities in the Canary Islands in particular are frequently reaching diffraction limited resolution and yield new insight in the structure and dynamics of the solar atmosphere. Future ground based telescopes like THEMIS and LEST, as well as planned solar missions in space will trigger a next advance in solar physics.

scholarly journals Three campaigns of solar observations with an astrolabe at Simeiz

1996 ◽  
Vol 172 ◽  
pp. 505-506 ◽  
Author(s):  
Yu. B. Kolesnik
Keyword(s):  
Sao Paulo ◽  
The Sun ◽  
São Paulo ◽  
Santiago De Chile ◽  
Solar Observations ◽  
Experimental Campaign ◽  
San Fernando

Positional observations of the Sun have become, in recent years, one of the most important contribution of astrolabes to fundamental astrometry. After pioneer observations at CERGA and Sao Paulo, both in 1974, other astrolabes have been adapted for observations of the Sun in Paris (now at Malatya, Turkey), Santiago de Chile (Chollet & Noël 1993) and San-Fernando (Sánchez et al. 1993, 1995). First experimental campaign of solar observations with an astrolabe installed at Simeiz Observatory (Crimea, Ukraine) has been undertaken in 1986 (Kolesnik 1987). After some instrumental improvements, observations covering about 2.5–3 months were continued in 1987, 1990, 1991. The results are reported here.

The Solaris Solar Polar Mission

2020 ◽  
Author(s):  
Donald M. Hassler ◽  
Jeff Newmark ◽  
Sarah Gibson ◽  
Louise Harra ◽  
Thierry Appourchaux ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Solar Physics ◽  
Polar View ◽  
Ecliptic Plane ◽  
Vantage Point ◽  
Mission Design ◽  
Future Research ◽  
The Sun ◽  
Gravity Assist ◽  
Solar Observations

<p>The solar poles are one of the last unexplored regions of the solar system. Although Ulysses flew over the poles in the 1990s, it did not have remote sensing instruments onboard to probe the Sun’s polar magnetic field or surface/sub-surface flows.</p><p>We will discuss Solaris, a proposed Solar Polar MIDEX mission to revolutionize our understanding of the Sun by addressing fundamental questions that can only be answered from a polar vantage point. Solaris uses a Jupiter gravity assist to escape the ecliptic plane and fly over both poles of the Sun to >75 deg. inclination, obtaining the first high-latitude, multi-month-long, continuous remote-sensing solar observations. Solaris will address key outstanding, breakthrough problems in solar physics and fill holes in our scientific understanding that will not be addressed by current missions.</p><p>With focused science and a simple, elegant mission design, Solaris will also provide enabling observations for space weather research (e.g. polar view of CMEs), and stimulate future research through new unanticipated discoveries.</p>

The Tanaka-Enome criterion and solar activity in October?November 2003 as observed by the Large Pulkovo Radio Telescope

2004 ◽  
Vol 42 (6) ◽  
pp. 561-570 ◽  
Author(s):  
T. P. Borisevich ◽  
G. N. Il?in ◽  
A. N. Korzhavin ◽  
N. G. Peterova ◽  
N. A. Topchilo ◽  
...  
Keyword(s):  
Solar Activity ◽  
Radio Telescope ◽  
Large Pulkovo Radio Telescope

scholarly journals The Needs and Requirements from the Standpoint of the Ultraviolet Solar Observations

1968 ◽  
Vol 1 ◽  
pp. 538-540
Author(s):  
E.M. Reeves
Keyword(s):  
Spatial Resolution ◽  
Time Resolution ◽  
Solar Disk ◽  
Emission Lines ◽  
High Time Resolution ◽  
The Sun ◽  
X Ray ◽  
Solar Observations ◽  
Partial Success

Extending from the present to the early part of 1969 there are three Orbiting Solar Observatories to be launched, and these will all be capable of constructing spectroheliograms of the Sun in solar emission lines of the EUV and X-ray region. The recently launched and highly successful OSO-III has obtained EUV and X-ray spectra with high-time resolution, but without spatial resolution on the solar disk. The later OSO satellites will provide spatial resolution of 1′ of arc to 30″ of arc, and will provide the basis for the extension to even higher spatial resolution in the future.The comparatively short periods covered by these satellites, coupled with a real probability of only partial success, make it particularly important to obtain the fullest possible use of the data by implementing a complementary and simultaneous series of ground-based observations.

scholarly journals The Vatly Radio Telescope: Performance Study

2014 ◽  
Vol 24 (3) ◽  
pp. 257 ◽  
Author(s):  
Nguyen Thi Phuong ◽  
Pham Ngoc Diep ◽  
Darriulat Pierre ◽  
Pham Tuyet Nhung ◽  
Pham Tuan Anh ◽  
...  
Keyword(s):  
Flux Density ◽  
Radio Telescope ◽  
Percent Level ◽  
Solar Flux ◽  
Detailed Account ◽  
The Sun ◽  
Performance Study ◽  
Flux Data ◽  
Spectral Flux ◽  
Electromagnetic Pollution

A detailed account of the performance of the VATLY radio telescope, operated in HaNoi on and near the 21 cm HI line, is given. Drift scans across the Sun are used to measure the dependence of the gain on frequency and power, revealing small nonlinearities at or below the percent level. Interferences associated with the electromagnetic pollution in the Ha Noi environment are described. The sensitivity of the instrument is discussed and demonstrated with the detection of the Crab. The reliability of the measurement of the spectral flux density is illustrated by comparing solar flux data measured in Ha Noi and at the Australian observatory of Learmonth.

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