Objective

In a microscope, the objective (also called the objective lens) is the lens nearest to the object being examined whereas the lens closest to the eye is termed the ocular (the eyepiece). The light microscope today is usually binocular (with one ocular for each eye) and has a turret bearing a selection of objective lens.

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1. The lens or lenses in the object end of the body tube of a microscope, by means of which the rays coming from the object examined are brought to a focus. SYN: object glass. 2. Viewing events or phenomena as they exist in the external world, impersonally, or in an unprejudiced way; open to observation by oneself and by others. Cf.:subjective. [L. ob- jicio, pp. -jectus, to throw before]

- achromatic o. an o. that is corrected for two colors chromatically, and one color spherically.

- apochromatic o. an o. in which chromatic aberration is corrected for three colors and spherical aberration is corrected for two.

- immersion o. a high power o. used with a drop of oil between the lens and the specimen on the slide, allowing a greater numerical aperture; similar lenses are available for use with water as the immersing liquid.

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ob·jec·tive əb-'jek-tiv, äb- adj

1) of, relating to, or being an object, phenomenon, or condition in the realm of sensible experience independent of individual thought and perceptible by all observers <\objective reality>

2) perceptible to persons other than the affected individual <an \objective symptom of disease> compare SUBJECTIVE (2b)

ob·jec·tive·ly adv

objective n

1) a lens or system of lenses that forms an image of an object

2) something toward which effort is directed

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n.

(in microscopy) the lens or system of lenses in a light microscope that is nearest to the object under examination and furthest from the eyepiece. In many types of microscope interchangeable objectives with different powers of magnification are provided.

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ob·jec·tive (ob-jekґtiv) [L. objectivus] 1. perceptible to the external senses. 2. a result for whose achievement an effort is made. 3. the lens or system of lenses in a microscope (or telescope) that is nearest to the object under examination.