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Stand magnifier low vision

Immersion Oil:  Clear, finely detailed images are achieved by contrasting the specimen with their medium.  Changing the refractive index of the specimens from their medium attains this contrast.  The refractive index is a measure of the relative velocity at which light passes through a material.  When light rays pass through the two materials (specimen and medium) that have different refractive indices, the rays change direction from a straight path by bending (refracting) at the boundary between the specimen and the medium.  Thus, this increases the image’s contrast between the specimen and the medium.

Magnifier Pendant

Resolving power or resolution: the ability to distinguish objects that are close together.  The better the resolving power of the microscope, the closer together two objects can be and still be seen as separate.

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Parfocal: the objective lenses are mounted on the microscope so that they can be interchanged without having to appreciably vary the focus.

Eschenbach Mobilux magnifying glass with light

Travel Magnifying Glass

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Bar magnifiers are a great solution for reading, because they can cover several lines of print at once. This makes it more comfortable to read, as you don’t have to move around as much while you read! This 1.5” wide and 9” long bar magnifier, which provides 1.5X magnification, lets you see several lines at the same time. The yellow highlighting line helps you keep track of the line you’re reading.

Total magnification: In a compound microscope the total magnification is the product of the objective and ocular lenses (see figure below).  The magnification of the ocular lenses on your scope is 10X.

One way to change the refractive index is by staining the specimen.  Another is to use immersion oil.  While we want light to refract differently between the specimen and the medium, we do not want to lose any light rays, as this would decrease the resolution of the image.  By placing immersion oil between the glass slide and the oil immersion lens (100X), the light rays at the highest magnification can be retained.  Immersion oil has the same refractive index as glass so the oil becomes part of the optics of the microscope.  Without the oil the light rays are refracted as they enter the air between the slide and the lens and the objective lens would have to be increased in diameter in order to capture them.  Using oil has the same effect as increasing the objective diameter therefore improving the resolving power of the lens.