scholarly journals Further observations on the spectrum of the night sky

1923 ◽  
Vol 103 (720) ◽  
pp. 45-52 ◽  
Keyword(s):  
Camera Lens ◽  
The Past ◽  
Light Gathering Power ◽  
Identical Construction ◽  
Light Gathering ◽  
Minimum Number ◽  
Night Sky ◽  
Collimating Lens ◽  
Past Winter

During the past winter I have continued my studies on the spectrum of the night sky, and the connected subject of the auroral spectrum. The present paper reports the results obtained. The spectrographs used in this work are two of nearly identical construction. In designing them the paramount consideration was to obtain the greatest possible light gathering power, all other considerations being kept subordinate to this. It was accordingly decided to use the minimum number of optical pieces—one prism, one collimating lens, one camera lens, neither of the latter to be achromatic.

Multilayer mirror systems to form hard X-ray beams

Open Physics ◽  
2005 ◽  
Vol 3 (2) ◽  
Author(s):  
Anton Akhsakhalyan ◽  
Aram Akhsakhlyan ◽  
Alexander Kharitonov ◽  
Eugenie Kluenkov ◽  
Vladimir Murav’ev ◽  
...  
Keyword(s):  
Multilayer Structure ◽  
High Light ◽  
Fabrication Technology ◽  
X Ray ◽  
Multilayer Mirror ◽  
The Past ◽  
Research Activities ◽  
Light Gathering Power ◽  
Light Gathering

AbstractThis paper is an overview of the research activities carried out in the past five years at the Institute for Physics of Microstructures RAS and “X-ray” Company towards the manufacture of multilayer mirror systems capable of forming X-ray beams in the subnanometer range of wavelengths. The systems fabrication technology is presented, including techniques for producing supersmooth surfaces of specified shape, methods of graded multilayer structure deposition on such surfaces, and the principles of designing optimal mirror parameters. The characteristics of a quadrelliptical reflector—a novel high light-gathering power four-corner focusing system—are reported.

scholarly journals IX.—Researches on Heat. Third Series. § 1. On the unequally Polarizable Nature of different kinds of Heat. § 2. On the Depolarization of Heat. §; 3. On the Refrangibility of Heat

1839 ◽  
Vol 14 (1) ◽  
pp. 176-207
Author(s):  
James D. Forbes
Keyword(s):  
Refractive Indices ◽  
The Third ◽  
The Past ◽  
Made In ◽  
Past Winter

1. The following paper is divided into three sections, containing three distinct yet intimately connected investigations. The two first on the Polarizability and Depolarization of Heat have arisen immediately out of the train of investigation contained in my two former papers, and the researches of others to which they gave rise. The third is on the Refrangibility of Heat, a point of the highest importance for theory.2. The experiments on which these investigations are based have been performed almost exclusively during the past winter. Part of the experiments on Depolarization were, however, made in the winter 1836-7. The mode adopted for trying Refractive Indices I had long ago contemplated. It was not, however, put in practice until January last.

The Solubility of Carbonate of Lime in Fresh and Sea Water

1890 ◽  
Vol 16 ◽  
pp. 319-324 ◽  
Author(s):  
W. S. Anderson
Keyword(s):  
Sea Water ◽  
The Past ◽  
Marine Station ◽  
Work Done ◽  
Past Winter

At Dr Murray's request, I have during the past winter continued the investigation of Messrs Irvine and Young on the solubility of carbonate of lime in its different forms in sea water (the results of which they submitted to this Society in May 1888); and the following notes of the work done and the results obtained by me, under Mr Irvine's guidance, in the laboratory of the Marine Station, Granton, may be of interest.

Merging Data from Large and Small Telescopes – Good or Bad? And: How Useful is the Application of Statistical Weights to Time-Series Photometric Measurements?

2003 ◽  
Vol 12 (2) ◽  
Author(s):  
G. Handler
Keyword(s):  
Fourier Transforms ◽  
Light Curves ◽  
Data Sets ◽  
Effective Number ◽  
Spectral Window ◽  
Light Gathering Power ◽  
Data Weighting ◽  
Light Gathering ◽  
Data Points ◽  
Photometric Measurements

AbstractI have investigated the value of the contribution of small telescopes to the success of a whole WET run. To this end, I have applied different data weighting schemes to two extreme WET test data sets. I find that weights proportional to the inverse local scatter in the light curves produce Fourier Transforms of best signal-to-noise. Weighting data stronger than their inverse scatter does not yield optimal results because of the reduction of the effective number of data points.The contribution of the small telescopes to the combined WET results was found to be very important. They do not only improve the spectral window, but they can reduce the noise in the total FT by more than their light gathering power would imply. Some suggestions for the optimal use of small telescopes in the WET are given.

scholarly journals Steam Punks

2011 ◽  
Vol 133 (06) ◽  
pp. 32-37
Author(s):  
Jefrey Winters
Keyword(s):  
Open Source ◽  
Induction Furnace ◽  
Modern Life ◽  
Hydraulic Power ◽  
The Past ◽  
Computer Numerically Controlled ◽  
Compressed Earth Block ◽  
Minimum Number ◽  
Earth Block ◽  
Web Platform

This article discusses how some amateur engineers are working to design and build a set of tools that would enable self-reliant people to make everything they need. Marcin Jakubowski and his colleagues are among such people who are working for the past many years on the concept of open-source economy. The rationale for this concept is steeped in the language of empowerment. Using an open-source Web platform known as a wiki, Jakubowski worked with a far-flung network of collaborators over the Internet to identify the minimum number of technologies needed to produce a reasonable facsimile of modern life. Some of the items on the resulting list are the greatest hits of industrialism over the past 200 years: the steam engine, the combine, and the induction furnace. So far, the team has completed seven prototype machines: the tractor, a tiller, a hydraulic power unit, a computer numerically controlled plasma torch table, a drill press, a hole punch, and a compressed earth block press.

scholarly journals Wide-Field-Imaging 3-Mirror-Systems by High Light Gathering Power and a Wide-Field Optical System for the ‘Large Imaging Telescope’ (Lite)

1994 ◽  
Vol 161 ◽  
pp. 101-107
Author(s):  
U. Laux
Keyword(s):  
Optical System ◽  
High Light ◽  
Field Of View ◽  
Wide Field ◽  
Light Gathering Power ◽  
Imaging Telescope ◽  
Light Gathering ◽  
Field Imaging ◽  
Wide Field Imaging

The desire of astronomers for wide field telescope systems which surpass the RCC (1:8 max. 1.5 degree) in light gathering power and field of view are relative concrete today. For this type of telescope, detectors planned ARE CCDs in multichip arrangement.

An analysis of rock magnetic data

1960 ◽  
Vol 256 (1286) ◽  
pp. 291-322 ◽  
Keyword(s):  
Magnetic Field ◽  
Continental Drift ◽  
Magnetic Data ◽  
Rotational Axis ◽  
Earth’S Magnetic Field ◽  
Geological Time ◽  
The Past ◽  
Geological Processes ◽  
Minimum Number ◽  
Earth's Magnetic Field

The data obtained from numerous palaeomagnetic measurements made during the past decade have shown that while the geologically younger rock formations are magnetized in directions close to that of the present earth’s magnetic field, the remanent magnetic polarizations of older rocks depart markedly from this pattern. These observations are widely held by many workers to suggest that the main continental land masses have undergone movements relative to one another during the past. The present paper gives an account of a new analysis of the available data, making a minimum number of theoretical assumptions about the ways in which the rocks became magnetized and about the origin of the geomagnetic field. The results of this analysis strongly support the supposition that the observed wide divergence between the directions of the remanent magnetic vectors of older rocks and that of the present earth’s field is systematic, and not a result of purely random processes occurring throughout geological time. The most reasonable explanations of the phenomenon appear to be that ( a ) the directions of magnetization of the earlier rocks have been changed by some widespread physical or geological processes since the time of their formation, ( b ) the earth’s magnetic field has had strong multipolar components in past geological ages, ( c ) a relative drift of the continents across the earth’s mantle has occurred. Of these hypotheses, ( c ) appears to be the most plausible. On the tentative assumption that the rock magnetic results can be explained by continental drift, it is possible to estimate the ancient latitude and the orientation relative to the earth’s rotational axis, of each continent, although by palaeomagnetic measurements alone changes in relative longitude cannot be revealed.

scholarly journals II. Note on some winter thermometric observations in the Alps

1874 ◽  
Vol 22 (148-155) ◽  
pp. 317-328 ◽  
Keyword(s):  
Winter Climate ◽  
Past Season ◽  
The Past ◽  
Summer Climate ◽  
Heated Air ◽  
The Alps ◽  
The Village ◽  
Solar Rays ◽  
Past Winter

During the past winter, I spent a. fortnight at the village of Davos, Canton Graubünden, Switzerland, and had thus an opportunity of experiencing some of the remarkable peculiarities of the climate of the elevated valley (the Prättigau) in which Davos is situated. The village has of late acquired considerable repute as a climatic sanitarium for persons suffering from diseases of the chest. So rapidly has its reputa­tion grown, that while in the winter of 1865—66 only eight patients resided there, during the past season upwards of three hundred have wintered in the valley. The summer climate of Davos is very similar to that of Pontresina and St. Moritz, in the neighbouring high valley of the Engadin—cool and rather windy; but so soon as the Prättigau and surrounding mountains become thickly and, for the winter, permanently covered with snow, which usually happens in November, a new set of conditions come into play and the winter climate becomes exceedingly remarkable. The sky is, as a-rule, cloudless or nearly so; and, as the solar rays, though very powerful, are incompetent to melt the snow, they have little effect upon the temperature, either of the valley or its enclosing mountains ; conse­quently there are no currents of heated air; and, as the valley is well sheltered from more general atmospheric movements, an almost uniform calm prevails until the snow melts in spring.

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