aberration of position
31Field (physics) — The magnitude of an electric field surrounding two equally charged (repelling) particles. Brighter areas have a greater magnitude. The direction of the field is not visible …
32optics — /op tiks/, n. (used with a sing. v.) the branch of physical science that deals with the properties and phenomena of both visible and invisible light and with vision. [1605 15; < ML optica < Gk optiká, n. use of neut. pl. of OPTIKÓS; see OPTIC,… …
33Transmission electron microscopy — A TEM image of the polio virus. The polio virus is 30 nm in size.[1] Transmission electron microscopy (TEM) is a microscopy technique whereby a beam of electrons is transmitted through an ultra thin specimen, interacting with the specimen as it… …
34Luminiferous aether — The luminiferous aether: it was hypothesised that the Earth moves through a medium of aether that carries light In the late 19th century, luminiferous aether or ether, meaning light bearing aether, was the term used to describe a medium for the… …
35Speed of gravity — In the context of classical theories of gravitation, the speed of gravity refers to the speed at which a gravitational field propagates. This is the speed at which changes in the distribution of energy and momentum result in noticeable changes in …
36Eyepiece — For the device for looking through a camera, see viewfinder. A collection of different types of eyepieces. An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes. It is… …
37Aberrations en optique des particules chargées — Les aberrations en optique des particules chargées sont l équivalent des aberrations en optique photonique. L étude des aberrations des lentilles électroniques est presque aussi vieille que le microscope électronique[1]. Il n y a pas de… …
38ASTROMÉTRIE ET ASTRONOMIE FONDAMENTALE — L’astrométrie est la partie de l’astronomie qui se propose de déterminer les positions des astres dans le ciel afin de pouvoir interpréter leurs variations dans le temps. Elle est donc la base observationnelle de l’étude dynamique des corps du… …
39New moon — For other uses, see New moon (disambiguation). The new moon phase In astronomical terminology, the new moon is the lunar phase that occurs when the Moon, in its monthly orbital motion around Earth, lies between Earth and the Sun, and is therefore …
40Optical telescope — Eight Inch refracting telescope (Chabot Space and Science Center) An optical telescope is a telescope which is used to gather and focus light mainly from the visible part of the electromagnetic spectrum for directly viewing a magnified image for… …
