| homogeneous immersion objective | <microscopy> An objective to be immersed in a liquid of a certain refractive index and dispersion value as specified by the manufacturer of the objective. An oil-immersion objective, the most important type, is intended to be immersed in cedarwood oil (nD = 1.515) or in its manmade optical equivalent. A water-immersion objective is for dipping into an aqueous specimen mount. Alpha-monobromonaphthalene has such a high refractive index (nD = 1.66) that a very highly resolving objective (1.60 numerical aperture) was designed to be immersed in that liquid, for use by reflected light on metals and other opaque objects. (05 Aug 1998) |
|---|---|
| semi-apochromatic objective | <microscopy> A compromise, in the correction for chromatic and spherical aberration, between achromatic and apochromatic objectives, such as a fluorite objective. (05 Aug 1998) |
| dark field objective | <microscopy> Certain objectives for high-power, dark fieldwork equipped with iris diaphragms or funnel stops so that their apertures may be reduced to correspond to the dark field con-denser with which they are used. (05 Aug 1998) |
| dry objective | <microscopy> Any microscope objective designed for use without immersion liquids. (05 Aug 1998) |
| immersion objective | <microscopy> An objective in which the medium of high refractive index and is used in the object space to increase the numerical aperture and hence the resolving power of the lens. See: homogeneous immersion of objective. (05 Aug 1998) |
| objective | 1. <psychology> Perceptible to the external senses. 2. <ophthalmology> The lens or system of lenses in a microscope (or telescope) that is nearest to the object under examination. Origin: L. Objectivus (18 Nov 1997) |
| objective circle | <microscopy> When the focused objective is examined by with- drawing the ocular and viewing its back focal plane through the microscope bodytube, the limiting boundary of the objective, the circumference of the white spot of light, is the objective circle. (05 Aug 1998) |
| objective, fluorite | <microscopy> An objective using the mineral fluorite in its construction. It is usually intermediate between achromatic and apochromatic in correction, but may be more highly corrected. See: illumination, eyepiece. (05 Aug 1998) |
| objective optometer | <optics> A contrivance for exhibiting and measuring the refraction of light. Origin: Refraction. Source: Websters Dictionary (01 Mar 1998) |
| objective perimetry | Determination of the visual field by pupillary constriction, electroencephalography, or eye movements. (05 Mar 2000) |
| objective probability | A probability of an outcome based either on unassailable theory or extensive empirical experience of exactly the same combination of circumstances; the notion also implies that the realization concerned has not been effected and therefore even in principle not known with certainty. (05 Mar 2000) |
| objective psychology | Psychology as studied by observation of the behaviour and mental functions in others. (05 Mar 2000) |
| objective sensation | A sensation caused by a verifiable stimulus. Primary sensation, a sensation that is the direct result of a stimulus. Referred sensation, a sensation felt in one place in response to a stimulus applied in another. Synonym: reflex sensation, transferred sensation. (05 Mar 2000) |
| objective sign | <clinical sign> A sign that is evident to the examiner. (05 Mar 2000) |
| objective symptom | A symptom that is evident to the observer. (05 Mar 2000) |