| 释义 |
Kellner, n.
Brit. |ˈkɛlnə|, U.S. |ˈkɛlnər|
[‹ the name of Karl Kellner (1826–55), German optical instrument maker, who introduced the eyepiece in 1849.]
I. Compounds.
1. attrib. Designating a compound eyepiece used esp. for telescopes, consisting of a planoconvex field lens and an eye lens that is an achromatic doublet.
1865Proc. Royal Soc. 14 46 In tracing the path of a ‘spot’ across the disk of the sun, I employ a Kellner (positive) eyepiece of about 50 linear. 1922E. Rutherford in Philos. Mag. 44 418 A modified form of Kellner eyepiece was constructed. 1969Jrnl. Brit. Astron. Assoc. 79 354 The proper description of this type is achromatic Ramsden, but it is often referred to as Kellner type. The eyepiece properly described as of Kellner type is that shown in figure 6, which has a double convex field lens with a cemented doublet eye lens having a concave surface facing the eye. 1998Mod. Astronomer Mar. 54/1 Accessories include a star diagonal and Kellner eyepieces of 25 millimetres (×35.4) and 10 millimetres (×91) focal length.
II. Simple uses.
2. A Kellner eyepiece.
1865Proc. Royal Soc. 14 46 Having..determined the positions of the spots, I replace the Kellner by ordinary (negative) eyepieces. 1922L. Bell Telescope vi. 145 The Kellner is decidedly valuable as a wide field positive ocular. 1969Jrnl. Brit. Astron. Assoc. 79 p. ii/2 (advt.) We have designed and manufactured a first-class ortho of 1/3{pp} focus and 45° field... Barlows, Ramsdens, Kellners stocked. 1995Sky & Telescope May 8/3 The effect is most pronounced in the least complex eyepieces, such as Kellners and Plössls. |