eyepiecen.
/ˈʌɪpiːs/, U.S. /ˈaɪˌpis/ 1. In an optical instrument (as a telescope, microscope, or camera): the lens or (more commonly) the group of lenses to which the eye is applied, and by which the image is magnified and viewed; = ocular n. 3.An eyepiece typically consists of several lenses in a single housing (cf. eye lens n. (a) at eye n.1 Compounds 4, field lens n. at field n.1 Compounds 5). Eyepieces can be distinguished according to the way the image is presented to the eye (whether upright or inverted), and where the image is formed in relation to the constituent lenses.Huyghenian, micrometer, negative, orthoscopic, positive eyepiece, etc.: see the first element.
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the world > physical sensation > sight and vision > optical instruments > lens > [noun] > eye-piece
eyeglass1665
ocular1702
eyepiece1729
Ramsden1787
field glass1797
negative eyepiece1831
positive eyepiece1842
Kellner1865
orthoscopic1868
eye-point1875
comparison eyepiece1940
1729 R. Browne Longitude 3 I have Contrived..to take Angles to about 10 Degrees with one Eye-piece.
1790 Philos. Trans. (Royal Soc.) 80 155 The common eye-piece with two convex glasses.
1819 A. Rees Cycl. XXXV. at Telescope Fig. 5 gives the arrangement of the lenses in a terrestrial achromatic telescope with a triple object-glass; in which A is the object-glass, B the eye-lens, and C the..field-lens of the eye-piece BC.
1854 J. Hogg Microscope i. ii. 30 The two, [sc. eye-glass and field-glass] when combined, are called the eye-piece.
1944 Pop. Mech. June 27/1 A soldier trainee looking in the eyepieces sees a moving, illuminated target.
1970 Jrnl. Brit. Astron. Assoc. 80 p. i (advt.) The Charles Frank extra-wide field 4-element eyepiece.
2009 New Yorker 26 Oct. 57/3 A dozen computers..fed the images, along with the digital set design, into the eyepiece of Cameron's ‘virtual camera’.
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1880 Leeds Mercury 16 Nov. 7 The power of a lazy free-selector to pick out the eye-piece of a squatter's run.
Compounds
eyepiece micrometer n. a scale of measurement inside an eyepiece that can be viewed at the same time as the image, on which it appears superimposed; an eyepiece incorporating such a scale.
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1813 D. Brewster Treat. New Philos. Instruments vii. 59 I sent a drawing and description of the eye-piece micrometer to Mr Carey.
1857 Q. Jrnl. Microsc. Sci. 5 47 The spores had essentially the same characters. As measured by an eye-piece micrometer..they generally varied in length from 1/ 1100 to 1/ 1500 inch.
1959 N.Z. Jrnl. Agric. Res. June 559 The cell heights were measured using an eye piece micrometer.
2011 H. D. Lujan & S. Svärd Giardia xxii. 357/2 The scale on the eye-piece micrometer and the image of the object are seen simultaneously.
This entry has been updated (OED Third Edition, June 2014; most recently modified version published online March 2022).
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n.1729