How is the magnifiction of binoculars / telescopes measured.?

Answer 1

It's the number of times the image appears to be magnified. "Kris" above gives the correct formula for calculating it: the focal length of the objective (front) lens system divided by the focal length of the eyepiece lens system.

Answer 2

BINOCULAR MAGNIFICATION (POWER)
Power of magnification:
Binoculars are often referred to by two numbers separated with an "x". For example; 8x32. The first number is the power or magnification of the binocular. With an 8x32 binocular, the object being viewed appears to be eight times closer than you would see it with the unaided eye. Many people ask - How far can you see with a binocular? - answer - You can see as far your eyes can see, but the objects will seem to be closer - magnified by the power of your binoculars.

OBJECTIVE LENS SIZE (APERTURE)
The second number in the formula (8x32) is the diameter of the objective or front lens. The larger the objective lens, the more light that enters the binocular, and the brighter the image.

Zoom Binocular
A binocular with a variable power range, for example: 8-20x. Magnification is changed with a convenient lever or knob allowing you to increase the magnification when you want to get in close for detail from a distance.

Telescopes:

Magnification (Power)
Telescopes are often referred to by two numbers separated by an "x". For example: 100x114mm. The first number is the power or magnification of the telescope. With a 100x114 telescope, the object being viewed appears to be 100 times closer than you would see it with the unaided eye. The magnification of a telescope is determined by dividing its focal length by the focal length of the eyepiece in use. For example, a 500mm telescope with a 5mm eyepiece would magnify objects 100x. Thus a telescope can provide nearly any magnification required depending on the focal length of the eyepiece used. Since most objects in the sky are rather large, high magnification isn't necessary. Rather, a telescope that gathers a lot of light is needed to make dim objects appear brighter and sharper. The power or magnification contributes to the overall size and bulk of the telescope. This is because as the power increases, so must the physical size of the objective lens.

Objective Lens Size (or Aperture)
The second number in the formula (100x114) is the diameter of the objective lens or mirror. The aperture relates directly to how bright images will appear and how much detail is revealed. The larger the objective lens the better. The size of the telescope's objective lens, or aperture, limits the amount of power that can be used effectively. As the magnification of an object increases, the brightness of the image decreases. This is because the light gathered by the telescope is being spread over a larger area. Aperture also limits the clarity of an image at increased magnification. When magnified beyond an aperture's recommended power, the image dims and becomes fuzzy.

Answer 3

A telescope's magnification depends on it's focal length and the focal length of the eyepiece being used, so the magnification is changeable.

For a telescopes: magnification = (telescope focal length)/(eyepiece focal length)

Both of these must be in the same units when calculating.

With binoculars, the magnification is printed on them. For example, 7x50 binoculars have a magnification of 7 times. 50 is the diameter of the larger lens in milimeters.

This should not be confused with when telescopes are listed as "420x60" In a telescope that means the focal length is 420 mm and the diameter of the primary lens (or mirror) is 60mm

Answer 4

its the amount of magnification and the size (diameter) of the len s ,so a 10 X50 binoculars would magnify 10 times and the lens would be 50 mm diameter. an 8X 40 would not be as powerful but would be smaller and lighter in weight.Also if you go over a 12X magnification you may need a tripod unless you have a steady hand! Ideal is a zoom pair as you can change the magnification

Answer 5

Most of the time in powers of magnification. A x2 magnification means that the object would appear to be twice as tall when viewed through the magnifier.

Another important measurement on a telescope is it's light gathering ability.

Answer 6

A person sees:

10 x 10 a person whose under 40

A person over 40 the aperture of the eye gets less.

Answer 7

In how many times they magnify an image. That is 10x binoculars will magnify more then 8x binoculars.

Answer 8

It's the ratio of the focal lengths of the objective lens/mirror to the eyepiece lens.

Answer 9

The ratio between:
the angle subtended by the object incident to the lens (in layman's terms, how big it looks to the naked eye)
and
the angle subtended by the object incident to the eye (how big it looks through the binocs)

Answer 10

good question