eye-piece, eyepiece n. (Opt.) The lens, or combination of lenses, at the eye end of a microscope, telescope or other optical instrument, through which the image formed by the mirror or object glass is viewed.
Synonyms:ocular.
Collimating eyepiece. See under Collimate.
Negative eyepiece, 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 eyepiece, 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.
... glass, before it is placed on the stage of the microscope. In focusing, do not allow the object glass of the microscope to come in contact with the cover glass. Focus upward, not downward. Special care should be exercised in focusing and in handling the eye-piece and objective. A camel's-hair brush, clean dry chamois skin, or clean silk only should be used in polishing the lenses. Always put the microscope back ... — Human Foods and Their Nutritive Value • Harry Snyder Read full book for free!
... and longitude there is nothing better than a small four or five inch theodolite not over fifteen pounds in weight. It should have a good prism eyepiece with an angle tube attached so it would not be necessary to break one's neck in reading high altitudes. For days we travelled in the direction the sun was going, with altitudes varying from 88 deg. to 90 deg.. Because of these high altitudes of the sun the sextant with ... — Through the Brazilian Wilderness • Theodore Roosevelt Read full book for free!