This principle is applied in darkfield (also called darkground) microscopy, a simple and popular method for making unstained transparent specimens clearly visible. Such objects often have refractive indices very close in value to that of their surroundings and are difficult to image in conventional brightfield microscopy. For instance, many small aquatic organisms have a refractive index ranging from 1.2 to 1.4, resulting in a negligible optical difference from the surrounding aqueous medium. These are ideal candidates for darkfield illumination.

Darkfieldillumination requires blocking out of the central light which ordinarily passes through and around (surrounding) the specimen, allowing only oblique rays from every azimuth to "strike" the specimen mounted on the microscope slide. The top lens of a simple Abbe darkfield condenser is spherically concave, allowing light rays emerging from the surface in all azimuths to form an inverted hollow cone of light with an apex centered in the specimen plane. If no specimen is present and the numerical aperture of the condenser is greater than that of the objective, the oblique rays cross and all such rays will miss entering the objective because of their obliquity. The field of view will appear dark.

SPECIFICATIONS

Body                :Main body all parts die casted to provide long life, Slide and objective protection via upward stage stopper.

EyePieces        :wide field 10x, 15x pairs

Objectives        : semi-plan achro objectives 4x, 10x, 40/45x s. L. 100x oil immersion (s. L.).withclarity

Dark Field Objective 100x(The darkfield condenser/objective pair illustrated above) and Dark field Condensor SET Eight magnification configurations: 40x, 60x, 100x, 150x, 400x, 600x, 1000x, 1500x. clarity glass optics with anti- fungus, anti reflection coating. All objectives are perfectly para-focused with no image shift thus reproducing sharp and clear images.

Binocular Observation Head: inclined at 45, rotateable through 360, interpupilary distance adjustment ring 54-74mm, dioptric adjustment ring on the left having adjustable dioptric scale.Dual side focusing controls

Focusing          :Coarse and fine focusing controls with single KNOB for precise focusing of the specimen. CONDENSER ; ABBE CONDENSER N. A. 1. 25 HAVING ASPHERICAL LENS, adjustable iris diaphragm Nosepiece       :quadruple nosepiece revolves on ballbearing

Illumination        : LED, with Smps based power supply i.ecompatiable for wide voltage range from 100v to 220volts

Packing            : Nicely Packed In Styrofoam Enclosure WithBox.

Others              : BREAKAGES ARE NOT COVERED INWARRANTY

Warranty          :12 Months For warranty-related claims, please contact the brand servicecentre.

Package dimen:54 x 44 x 30 cm weight: 5.5 kg