Thesaurus: eyepiece

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1. n. The lens, or combination of lenses, at the eye end of a telescope or other optical instrument, through which the image formed by the mirror or object glass is viewed.
2. n. combination of lenses at the viewing end of optical instruments
3. The lens, or combination of lenses, at the eye end of a telescope or other optical instrument, through which the image formed by the mirror or object glass is viewed. Collimating eyepiece. See under Collimate. -- Negative, or Huyghenian, eyepiece, an eyepiece consisting of two plano-convex lenses with their curved surfaces turned toward the object glass, and separated from each other by about half the sum of their focal distances, the image viewed by the eye being formed between the two lenses. it was devised by Huyghens, who applied it to the telescope. Campani applied it to the microscope, whence it is sometimes called Campani's eyepiece. -- Positive eyepiece, an eyepiece consisting of two plano-convex lenses placed with their curved surfaces toward each other, and separated by a distance somewhat less than the focal distance of the one nearest eye, the image of the object viewed being beyond both lenses; -- called also, from the name of the inventor, Ramsden's eyepiece. -- terrestrial, or Erecting eyepiece, an eyepiece used in telescopes for viewing terrestrial objects, consisting of three, or usually four, lenses, so arranged as to present the image of the object viewed in an erect position.
4. The lens, or combination of lenses, at the eye end of atelescope or other optical instrument, through which the image formedby the mirror or object glass is viewed. Collimating eyepiece. Seeunder Collimate.-- Negative, or Huyghenian, eyepiece, an eyepiece consisting of twoplano-convex lenses with their curved surfaces turned toward theobject glass, and separated from each other by about half the sum oftheir focal distances, the image viewed by the eye being formedbetween the two lenses. it was devised by Huyghens, who applied it tothe telescope. Campani applied it to the microscope, whence it issometimes called Campani's eyepiece.-- Positive eyepiece, an eyepiece consisting of two plano-convexlenses placed with their curved surfaces toward each other, andseparated by a distance somewhat less than the focal distance of theone nearest eye, the image of the object viewed being beyond bothlenses; -- called also, from the name of the inventor, Ramsden'seyepiece.-- terrestrial, or Erecting eyepiece, an eyepiece used in telescopesfor viewing terrestrial objects, consisting of three, or usuallyfour, lenses, so arranged as to present the image of the objectviewed in an erect position.
5. n:100 n. combination of lenses at the viewing end of optical instruments