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Transactions of the Society of Motion Picture Engineers ( Volume: 5, Issue: 13, 1921)
[ACTIVE]

A Point Light Source for Laboratory Use

Metadata

Publisher
SMPTE
Doc Type
Journal Article
Article Type
research-article
Abstract
The term “Point Light Source” is frequently made use of in the calculation and discussion of optical matters. It should always be kept in mind, however, that such a source is only hypothetical and represents a theoretical limit that is unattainable by any means whatever. In a quite similar manner, textbooks on optics give explanations and even formulae for calculating lenses on the basis of a lens with infinitesimal or zero thickness. These theoretical concepts are, of course, of considerable value in working out an optical system, and their use for such purposes should not be decried. In fact, some such assumptions are almost a necessity for the practical development of applied optics, but the fact remains that they are only hypothetical assumptions which can never be realized, and allowance must always be made for the finite or actual dimensions of the real physical light source. The astronomical telescope may perhaps be an exception, for the fixed stars as seen from the earth are point light sources for all but the most extremely delicate apparatus. In the observation of stars, however, another difficulty is encountered, i. e., the image of the star is not a point but has quite appreciable dimensions due to diffraction.
Publication Date
1921-01-01
DOI
10.5594/J12473
Link
https://doi.org/10.5594/J12473
Author(s)
C. A. B. Halvorson, S. C. Rogers
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C. A. B. Halvorson and S. C. Rogers; A Point Light Source for Laboratory Use, Transactions of the Society of Motion Picture Engineers ( Volume: 5, Issue: 13, 1921); SMPTE, 1921. Available at https://doi.org/10.5594/J12473
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C. A. B. Halvorson and S. C. Rogers; A Point Light Source for Laboratory Use, Transactions of the Society of Motion Picture Engineers ( Volume: 5, Issue: 13, 1921); SMPTE, 1921. Available at https://doi.org/10.5594/J12473

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C. A. B. Halvorson and S. C. Rogers; A Point Light Source for Laboratory Use, Transactions of the Society of Motion Picture Engineers ( Volume: 5, Issue: 13, 1921); SMPTE, 1921. Available at https://doi.org/10.5594/J12473
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<span class="citation">C. A. B. Halvorson and S. C. Rogers; <cite>A Point Light Source for Laboratory Use</cite>, Transactions of the Society of Motion Picture Engineers ( Volume: 5, Issue: 13, 1921); SMPTE, 1921. Available at <a href="https://doi.org/10.5594/J12473" target="_blank" rel="noopener">https://doi.org/10.5594/J12473</a></span>

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C. A. B. Halvorson and S. C. Rogers; A Point Light Source for Laboratory Use, Transactions of the Society of Motion Picture Engineers ( Volume: 5, Issue: 13, 1921); SMPTE, 1921
doi: 10.5594/J12473
url: https://doi.org/10.5594/J12473
Snippet:
<li>
C. A. B. Halvorson and S. C. Rogers; <cite id="bib-10-5594-j12473">A Point Light Source for Laboratory Use</cite>, Transactions of the Society of Motion Picture Engineers ( Volume: 5, Issue: 13, 1921); SMPTE, 1921
<span class="doi">10.5594/J12473</span>
</li>