英语词汇“focal aperture”的英英意思、用法、释义、翻译、读音、例句、短语、词组-英语词典

focal aperture n. Optics and Photography (a) the aperture at the focal plane of a telescope or other optical instrument (now rare); (b) a measure of the light-collecting power of a lens, telescope, etc.; = relative aperture n. at relative n., adj., and adv. Compounds.

ΚΠ

1841 Civil Engineer & Architect's Jrnl. 4 424/1 For instance, the diaphragm or focal aperture of a 20 inch telescope is ·39 inches.

1910 Nature 20 Jan. 339/1 In the common focal plane of the telescope objective and eye-piece,..a small totally reflecting prism is arranged, half covering the focal aperture.

1956 T. L. Gunn Photogr. in Garden iv. 43 To..secure reasonable definition on a windy day, it may be necessary to effect a compromise between exposure and the most effective focal aperture.

1986 Proc. SPIE (Internat. Soc. Optical Engin.) 645 85 The focal aperture of these lenses is around F/2.5 although faster lenses ~F/1 are routinely manufactured utilising the same techniques.

2013 Geospatial Today (Nexis) 27 Sept. Also, it is possible to track tiny bodies using telescopes with large focal aperture.

单词	focal aperture
释义	> as lemmas focal aperture focal aperture n. Optics and Photography (a) the aperture at the focal plane of a telescope or other optical instrument (now rare); (b) a measure of the light-collecting power of a lens, telescope, etc.; = relative aperture n. at relative n., adj., and adv. Compounds. ΚΠ 1841 Civil Engineer & Architect's Jrnl. 4 424/1 For instance, the diaphragm or focal aperture of a 20 inch telescope is ·39 inches. 1910 Nature 20 Jan. 339/1 In the common focal plane of the telescope objective and eye-piece,..a small totally reflecting prism is arranged, half covering the focal aperture. 1956 T. L. Gunn Photogr. in Garden iv. 43 To..secure reasonable definition on a windy day, it may be necessary to effect a compromise between exposure and the most effective focal aperture. 1986 Proc. SPIE (Internat. Soc. Optical Engin.) 645 85 The focal aperture of these lenses is around F/2.5 although faster lenses ~F/1 are routinely manufactured utilising the same techniques. 2013 Geospatial Today (Nexis) 27 Sept. Also, it is possible to track tiny bodies using telescopes with large focal aperture. extracted from focaladj. < as lemmas
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> as lemmas