Sturm’s relations governing the behavior of thin pencils of rays is applied to skew refraction at toric surfaces. The general relations are simplified and an estimate of the resulting error is derived. Exact results ...
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Sturm’s relations governing the behavior of thin pencils of rays is applied to skew refraction at toric surfaces. The general relations are simplified and an estimate of the resulting error is derived. Exact results are presented for the 45° intermediate plane trace at 30° vista angle in a −4.00-diopter sphere combined with a 4.00-diopter convex cylinder toric lens. An alternate skew toric trace is described.
SYNOPSISThe determination of the altitude of bodies above the surface of the earth has interested physicists, meteorologists, balloonists, mountain climbers, and aviators. The methods used have been similar and rest o...
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SYNOPSISThe determination of the altitude of bodies above the surface of the earth has interested physicists, meteorologists, balloonists, mountain climbers, and aviators. The methods used have been similar and rest on facts which have been well known for a long time. This paper is confined to the theory and methods of the accurate determination of altitude of aircraft above the earth’s surface and brings together all of the well known facts and methods in addition to some new *** is here emphasized that for aviation purposes, the altitude is determined by observations of pressure and temperature. A relation of pressure and temperature to altitude is derived. This expression is:in which h is the altitude in feet, P 0 is the atmospheric pressure at the ground level, P is the pressure at the upper level, and t m is the mean temperature of vertical column of air between the two levels.A more complete expression for the altitude is also derived in which the factors of slight practical importance are included. These factors are those of humidity and *** observations of pressure and temperature necessary to determine an altitude are discussed. The instruments used to make these observations are briefly *** method of computation of the altitude from these observations is outlined and illustrated by a sample *** paper concludes with tables of upper air data, aircraft performance standards and altimeter calibration standards for the United States and other countries.
Exact expressions have been derived from the Mie equations for the angular distribution coefficients, a n , in the equation,proposed by Hartel for the fraction of randomly polarized radiation scattered by a spherical ...
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Exact expressions have been derived from the Mie equations for the angular distribution coefficients, a n , in the equation,proposed by Hartel for the fraction of randomly polarized radiation scattered by a spherical particle into a unit solid angle in the direction θ . The coefficients are functions of the wavelength, particle diameter, and physical properties, and P n (cos θ ) are the Legendre polynomials. This equation is shown to be more convenient in form for tabulation of the scattering properties and for application than the intensity functions used by Mie and most subsequent investigators. Approximate methods for evaluating the coefficients were found to be inaccurate or inconvenient. The exact expressions, although detailed, are suitable for straightforward computation.
An electronic digital tristimulus integrator with interchangeable punched-tape programs corresponding to different illuminants or receptors has been constructed as an accessory for the General Electric Recording Spect...
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An electronic digital tristimulus integrator with interchangeable punched-tape programs corresponding to different illuminants or receptors has been constructed as an accessory for the General Electric Recording Spectrophotometer. The selected-ordinate principle is used. At least one-hundred ordinates are used for the Y integrations. The numbers of X and Z ordinates used are such as to eliminate the need for the adjustment factors usually used. The tristimulus values are presented visually.
In the course of the design of an optical system a knowledge of higher order aberration coefficients and of the contributions thereto by the individual surfaces is of great value. The present paper provides a computin...
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In the course of the design of an optical system a knowledge of higher order aberration coefficients and of the contributions thereto by the individual surfaces is of great value. The present paper provides a computing scheme for the full set of tertiary (and of course primary and secondary) monochromatic aberration coefficients of symmetrical optical systems composed of spherical surfaces. This particular scheme is intended for use with ordinary desk calculating machines, and comprises only 192 entries of the usual kind per surface. The method of construction of the scheme is discussed, and a complete numerical example provided. The checks used to ensure the correctness of the scheme at the same time test the correctness of certain long sets of equations contained in the author’s monograph on optical aberration coefficients; and one misprint in them was thus discovered. This is corrected here. A new nomenclature for higher order aberrations is proposed.
Certain disadvantages and limitations in conventional methods of measuring wavelengths from grating spectrograms are discussed, and some alternative procedures described. It is shown that by fitting thorium standards ...
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Certain disadvantages and limitations in conventional methods of measuring wavelengths from grating spectrograms are discussed, and some alternative procedures described. It is shown that by fitting thorium standards to the dispersion of the Argonne 9.15-m spectrograph, using a polynomial least-squares program with a digital computer, wavelengths accurate to 1 in 10 8 can be obtained at a rate of 1000 per day.
The methods used to compute tristimulus specifications are all approximate. In order to obtain information about the accuracy of the different weighted ordinate and selected ordinate methods, computed color values are...
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The methods used to compute tristimulus specifications are all approximate. In order to obtain information about the accuracy of the different weighted ordinate and selected ordinate methods, computed color values are compared for a number of reflecting surfaces and filters. The earlier data of Nickerson have been used for some of these comparisons. The only method, which determines the tristimulus specifications of all the samples studied with an uncertainty smaller than 1 2 jps (just perceptible steps), is the weighted ordinate method Δλ=5 m μ . To calculate the tristimulus specifications with an uncertainty of 1 2 NBS unit, the weighted ordinate method Δλ=10 m μ and the selected ordinate method N =100 are accurate enough, but the selected ordinate method N =30 must be rejected.
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