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11. |
Cemented Doublets |
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Optica Acta: International Journal of Optics,
Volume 29,
Issue 6,
1982,
Page 807-822
M. Iqbal Khan,
J. Macdonald,
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摘要:
A method for the rapid design of thin-lens cemented doublets for any primary aberration targets and based on a set of precomputed graphs is described. In effect, a modified and normalized version of the quintic expression in power distribution used by earlier workers is evaluated for a mesh over the whole spread of doublet solution space, and the results displayed in isometric plot form. The graphs not only permit aberration compromising near the target values, but also provide a direct indication of the practical acceptability of the solutions based on the steepness of the surface curvature involved. Two simple examples are presented.
ISSN:0030-3909
DOI:10.1080/713820915
出版商:Taylor & Francis Group
年代:1982
数据来源: Taylor
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12. |
Diffraction, Asymptotics and Catastrophes |
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Optica Acta: International Journal of Optics,
Volume 29,
Issue 6,
1982,
Page 823-842
Jakob J. Stamnes,
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PDF (1223KB)
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摘要:
First the method of stationary phase is used to develop various semiuniform asymptotic techniques that can be used to calculate the field in regions in which diffraction catastrophes occur. Three types of catastrophes are treated, namely those that take place at a shadow boundary, at a caustic and at a cusp. Then the diffraction of a spherical wave by a circular aperture is considered, and it is shown how the use of standard diffraction theories leads to diffraction integrals that can be evaluated by means of the semi-uniform asymptotic techniques developed for the three diffraction catastrophes mentioned above. Finally, it is pointed out how the asymptotic results provide new physical insight into the diffraction process, as well as offering great savings in computing time.
ISSN:0030-3909
DOI:10.1080/713820921
出版商:Taylor & Francis Group
年代:1982
数据来源: Taylor
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13. |
Colour Photography by Speckle Interferometry in White Light |
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Optica Acta: International Journal of Optics,
Volume 29,
Issue 6,
1982,
Page 843-846
J. Montilla,
R. Hernandez,
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PDF (247KB)
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摘要:
A method for recording, on black and white photographic emulsion, the image of coloured objects is described. For this purpose, we have used an interferential device by division of wavefront. The reconstruction of this image with the colours of the object is explained.
ISSN:0030-3909
DOI:10.1080/713820908
出版商:Taylor & Francis Group
年代:1982
数据来源: Taylor
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14. |
Le Témos 4 Une Solution Française Au Problème Du Télescope Mosaïque |
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Optica Acta: International Journal of Optics,
Volume 29,
Issue 6,
1982,
Page 847-860
A. Baranne,
G. Lemaître,
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PDF (1741KB)
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摘要:
Avec un correcteur fixe au foyer Cassegrain d'un télescope, il est possible d'utiliser un miroir primaire sphérique. Pour un Cassegrain àf/6,66 avec un primaire àf/2,5, trois correcteurs à deux lentilles sont présentés; le meilleur d'entre eux donne des aberrations résiduelles de 0,3 seconde d'arc sur un champ de 10 minutes d'arc. La segmentation du primaire en quatre miroirs dans un carré inscrits la conduit à un système compact et bon marché. Cette solution a aussi des avantages pour l'obturation centrale qui est réduite et, dans le cas de la spectroscopie, pour une utilisation plus efficace de la surface des réseaux. L'asphéricité du miroir secondaire peut être obtenue en utilisant le procédé de relaxation élastique appliqué à une forme “fond de vase”. Le tube du télescope est composé de huit barres situées dans les plans méridiens laissés libres par les quatre miroirs primaires. Pour réduire la flexion du tube, les quatre barres situées dans la monture alt-azimutale sont maintenues en condition de tension constante par des vérins hydrauliques actifs. Deux dispositifs de réglage asservi supplémentaires sont nécessaires pour obtenir la fusion de l'image et compenser la rotation du champ.
ISSN:0030-3909
DOI:10.1080/713820919
出版商:Taylor & Francis Group
年代:1982
数据来源: Taylor
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15. |
Holographic Interferometer, Proof Against External Vibrations |
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Optica Acta: International Journal of Optics,
Volume 29,
Issue 6,
1982,
Page 861-865
Satoru Toyooka,
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PDF (456KB)
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摘要:
A simple holographic interferometer for observing a phase object is presented. The optical system is constructed by a cascade-type coherent double diffraction system with two spatial filters. Since the object beam and the reference beam take a common path, the interferometer is proof against external vibrations. The interferometer is able to obtain not only an ordinary interferogram but also a phase contrast image or a differential interference contrast (DIC) image.
ISSN:0030-3909
DOI:10.1080/713820911
出版商:Taylor & Francis Group
年代:1982
数据来源: Taylor
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