scholarly journals Observation of Global 160-min Infrared (Differential) Intensity Variation of the Sun

1983 ◽  
Vol 66 ◽  
pp. 21-35
Author(s):  
V.A. Kotov ◽  
S. Koutchmy ◽  
O. Koutchmy
Keyword(s):  
Low Frequency ◽  
Intensity Variation ◽  
Solar Limb ◽  
The Sun ◽  
Average Amplitude ◽  
Instrument Analysis ◽  
Limb Intensity ◽  
Limb Darkening ◽  
Global Fluctuations ◽  
Made In

AbstractThe method developed and the instrument designed for detecting variations of the solar limb darkening at the atmospheric transparency window of the solar opacity minimum region of λ 1.65 µ are described. This differential technique proved to be successful in rejecting undesirable low frequency noises due to the atmosphere and to the instrument. Analysis of observations made in 1977, 1978, and 1981 indicates the persistance of global fluctuations of the IR differential, center-to-limb intensity at the wellknown 160 min period with an average amplitude of about ± 2 x 10-4 in units of the ‘average Sun’ intensity near 1.65 µm.

scholarly journals TOWARDS A UNIFIED DEFINITION OF SOLAR LIMB DURING CENTRAL ECLIPSES AND DAILY TRANSITS

2012 ◽  
Vol 12 ◽  
pp. 405-413
Author(s):  
COSTANTINO SIGISMONDI ◽  
ANDREA RAPONI ◽  
CYRIL BAZIN ◽  
RICHARD NUGENT
Keyword(s):  
Solar Limb ◽  
Light Signal ◽  
Light Curves ◽  
Emission Lines ◽  
The Sun ◽  
Simple Criterion ◽  
Definition Of ◽  
Limb Darkening ◽  
Function Reconstruction

The diameter of the Sun has been measured using Baily's beads during central eclipses, observed with portable telescopes. A blend of tiny emission lines produced in the first several hundred kilometers above the photosphere gives a light signal which prolonges the light curves of the beads. The simple criterion of light OFF/ON adopted in the previous approaches to define the timing of photosphere's disappearance/reappearance is modified. The technique of the limb darkening function reconstruction from the Baily's beads light curves is introduced here.

Solar Limb Darkening Color Imaging of the Sun with the Extreme Brightness Capability CAOS Camera

2020 ◽  
Vol 2020 (1) ◽  
pp. 69-73
Author(s):  
Nabeel A. Riza ◽  
Mohsin A. Mazhar ◽  
Nazim Ashraf
Keyword(s):  
Image Data ◽  
Solar Limb ◽  
Integration Time ◽  
The Sun ◽  
Cmos Camera ◽  
Full Spectrum ◽  
Optical Attenuation ◽  
Cmos Sensor ◽  
Small Factor ◽  
Limb Darkening

Experimentally demonstrated for the first time is Coded Access Optical Sensor (CAOS) camera-based imaging of the Sun. Only by using both the shortest 0.029 ms integration time of the scientific CMOS sensor and a very large factor of 10,000 optical attenuation at the entrance of the CMOS camera, one is able to produce the desired unsaturated image of the Sun. In sharp contrast, a small factor of 3.2 optical attenuation is required over a much smaller single photo-detector zone of the CAOS camera to capture the unsaturated Sun image, including color images obtained using red, green, and blue filters. Image data processing shows that both the CMOS camera and CAOS camera show similar Sun limb darkening measurements consistent with prior-art works. The CAOS camera empowers optically and operationally efficient full spectrum (e. g., 350 nm to 2700 nm) imaging of bright heavenly bodies in space, with the potential for creating impact for solar energy farms, space navigation, space exploration and astronomical science.

scholarly journals Space Studies of the Black-Drop Effect at a Mercury Transit

2005 ◽  
Vol 13 ◽  
pp. 70-72 ◽  
Author(s):  
Glenn Schneider ◽  
Jay M. Pasachoff ◽  
Leon Golub
Keyword(s):  
Solar System ◽  
21St Century ◽  
High Spatial Resolution ◽  
Solar Limb ◽  
The Sun ◽  
Point Spread ◽  
Spread Function ◽  
The Face ◽  
Limb Darkening

AbstractTransits of Mercury and Venus across the face of the Sun are rare. The 20th century had 15 transits of Mercury and the 21st century will have 14, the two most recent occurring on 15 November 1999 and 7 May 2003. We report on our observations and analysis of a black-drop effect at the 1999 and 2003 transits of Mercury seen in high spatial resolution optical imaging with NASA’s Transition Region and Coronal Explorer (TRACE) spacecraft. We have separated the primary contributors to this effect, solar limb darkening and broadening due to the instrumental point spread function, for the 1999 event. The observations are important for understanding historical observations of transits of Venus, which in the 18th and 19th centuries were basic for the determination of the scale of the solar system. Our observations are in preparation for the 8 June 2004 transit of Venus, the first to occur since 1882. Only five transits of Venus have ever been seen – in 1639, 1761, 1769, 1874, and 1882. These events occur in pairs, whose members are separated by 8 years, with an interval between pairs of 105 or 122 years. Nobody alive has ever seen a transit of Venus.

Examination of Thermal and Electrical Performance of Cassegrain Concentrator System

2019 ◽  
Vol 8 (6S2) ◽  
pp. 96-98
Keyword(s):  
Stainless Steel ◽  
Great Degree ◽  
Electrical Performance ◽  
Personal Satisfaction ◽  
The Sun ◽  
Supporting Structure ◽  
Apex Point ◽  
Control Water ◽  
Working Liquid ◽  
Made In

The sun oriented power (SP) is a one of a kind renewable vitality innovation. SP frameworks can give control, water warming and water decontamination in one unit. This innovation will be to a great degree accommodating in enhancing the personal satisfaction for some individuals around the globe who do not have the vitality expected to carry on with a sound life. A financial allegorical dish sort Cassegrain concentrating framework was created at the foundation of Energy Studies, Anna University Chennai. An old microwave media transmission reception apparatus having a paraboloidal shape made in aluminum frames an essential reflector which guarantees effortlessness of generation and operation. The essential concentrator was settled with mirror cleaned stainless steel with reasonable cement .The optional concentrator is inward mirror .Suitable supporting structure was developed for supporting the cassegrain concentrator. Double hub following framework is mounted for adjusting the concentrator to azimuth and apex point by utilizing DC engine and direct actuator individually. Water goes about as working liquid to expel warm from .The tank is protected with thermocol material upheld with wooden structure on all sides to maintain a strategic distance from convection misfortunes. The material Cost for the framework was Rs 15000

The Starry Universe of Jacques Cassini: Century-old Echoes of Kepler

2021 ◽  
Vol 52 (2) ◽  
pp. 147-167
Author(s):  
Christopher M. Graney
Keyword(s):  
18Th Century ◽  
The Sun ◽  
Johannes Kepler ◽  
Apparent Diameter ◽  
Early 18Th Century ◽  
Made In

This paper discusses measurements of the apparent diameter and parallax of the star Sirius, made in the early 18th century by Jacques Cassini, and how those measurements were discussed by other writers. Of particular interest is how other writers accepted Cassini’s measurements, but then discussed Sirius and other stars as though they were all the same size as the sun. Cassini’s measurements, by contrast, required Sirius and other stars to dwarf the sun—something Cassini explicitly noted, and something that echoed the ideas of Johannes Kepler more than a century earlier.

scholarly journals III. On the nature and construction of the sun and fixed stars

1795 ◽  
Vol 85 ◽  
pp. 46-72 ◽  
Keyword(s):  
Central Body ◽  
Planetary System ◽  
Considerable Progress ◽  
The Sun ◽  
Great Satisfaction ◽  
The Earth ◽  
The World ◽  
Celestial Bodies ◽  
The Universe ◽  
Made In

Among the celestial bodies the sun is certainly the first which should attract our notice. It is a fountain of light that illuminates the world! it is the cause of that heat which main­tains the productive power of nature, and makes the earth a fit habitation for man! it is the central body of the planetary system; and what renders a knowledge of its nature still more interesting to us is, that the numberless stars which compose the universe, appear, by the strictest analogy, to be similar bodies. Their innate light is so intense, that it reaches the eye of the observer from the remotest regions of space, and forcibly claims his notice. Now, if we are convinced that an inquiry into the nature and properties of the sun is highly worthy of our notice, we may also with great satisfaction reflect on the considerable progress that has already been made in our knowledge of this eminent body. It would require a long detail to enumerate all the various discoveries which have been made on this subject; I shall, therefore, content myself with giving only the most capital of them.

FUNGI IN AIR MASSES OVER MONTREAL DURING 1950 AND 1951

1956 ◽  
Vol 34 (1) ◽  
pp. 1-15 ◽  
Author(s):  
S. M. Pady ◽  
L. Kapica
Keyword(s):  
Seasonal Variation ◽  
Pollen Grains ◽  
Average Concentration ◽  
Yeast Cells ◽  
The Sun ◽  
Air Masses ◽  
Air Sampler ◽  
Agricultural Areas ◽  
Very High ◽  
Made In

Numbers and kinds of fungi were determined from nutrient plate and silicone slide studies from the roof of the Sun Life Building, Montreal, between September 1950 and December 1951. Exposures of plates were made in the General Electric Bacterial Air Sampler, and plates and silicone slides in the Bourdillon Slit Sampler. A total of 978 exposures was made on 113 sampling days during 16 months; 507 plates in the G. E. Sampler, 344 plates and 127 slides in the Slit Sampler. Of 40,359 colonies examined, Cladosporium, Penicillium, yeasts, Aspergillus, Alternaria, and Actinomycetes were commonest, constituting 47.7, 15.8, 10.4, 4.6, 4.2, and 2.2% of the total. The next commonest fungi were Pullularia, Oöspora, Fusarium, Stemphylium, Verticillium, Rhizopus, Spicaria, Scopulariopsis, Phoma, Mucor, Botrytis, Cephalosporium, Trichoderma, Helmin-thosporium, Neurospora, Papularia, Cephalothecium, Pyrenochaeta, Zythia, and Nigrospora. In addition 12 genera were infrequently found. Unidentified colonies numbered 174 and nonsporulating 3371 (8.3%). On a cubic foot basis numbers in the plates varied from 17.7 per cu. ft. in August to 0.4 per cu. ft in February.Fungus spores showed a seasonal variation with summer highs averaging 244 per cu. ft. in July to a low of 0.8 per cu. ft. in December. The most abundant spores were Cladosporium, yeasts, smuts, Fusarium, Alternaria, Venturia-like, Stemphylium, rusts, Septoria, and Helminthosporium. Hyphal fragments and pollen grains were present also. On eight occasions during the summer, readings of over 200 spores per cu. ft. were recorded, the maximum being 445 per cu. ft. on September 6, 1951. Cladosporium in August reached a peak of 74.1 per cu. ft. and yeast cells in July had an average concentration of 100 per cu. ft.An analysis of the air masses indicated that pure polar air carried low numbers of fungi, whereas tropical air had very high numbers. Most of the air masses were modified polar air and their fungus content varied considerably. The fungi in the air over Montreal are believed to have had their origin in agricultural areas.

scholarly journals XXXIV. On the transit of Venus in 1769. To the Right Honourable The Earl of Morton, President to the Council and Fellows of the Royal Society, this discourse is, with all humility, inscribed, by their humble servant, Thomas Hornsby

1765 ◽  
Vol 55 ◽  
pp. 326-344 ◽  
Keyword(s):  
Royal Society ◽  
The Sun ◽  
The Real ◽  
The Earth ◽  
Theory Of Gravity ◽  
The Right ◽  
Made In

The observations of the late transit of Venus, though made with all possible care and accuracy, have not enabled us to determine with certainty the real quantity of the sun's parallax; since, by a comparison of the observations made in several parts of the globe, the sun's parallax is not less than 8" 1/2, nor does it seem to exceed 10". From the labours of those gentlemen, who have attempted to deduce this quantity from the theory of gravity, it should seem that the earth performs its annual revolution round the sun at a greater distance than is generally imagined: since Mr. Professor Stewart has determined the sun's parallax to be only 6', 9, and Mr. Mayer, the late celebrated Professor at Gottingen, who hath brought the lunar tables to a degree of perfection almost unexpected, is of opinion that it cannot exceed 8".

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