Info-Authority.com: Binoculars

Binoculars are a tool used to magnify distant images. They consist of two small telescopes attached, side-by-side, to correspond with the length of the viewer's eyespan. The dual design allows the viewer to perceive objects in three dimensions, in contrast to a telescope, which distorts the depth of the image due to the limitations of viewing an object through a single eye. Binoculars possess the further advantage of being less bulky (and thus more portable) than telescopes, which routinely require a tripod or other heavy mount to operate. On average, binoculars are also far less expensive to produce. These advantages come at the expense of magnification power, which averages six to 10 times for an average pair. By contrast, a good backyard telescope can resolve anywhere from 20 to 60 times magnification.

Binocular Lenses

Binoculars operate on the same principle as eyeglasses, which use curved lenses to gather light to the eye in order to distort an image's apparent size. Binoculars make use of two lenses: the ocular lens, where the eye is placed, and the objective lens, found at the far end. Light is gathered into the objective lens and reflected back and forth by a series of prisms found in the tube itself, thereby increasing depth perception and allowing for the compact design of the binoculars themselves. Without such reflection, light would be required to traverse down a much larger tube to be enhanced. The more complex the prism, the more reflection that occurs, which in turn allows for a tube with less length and bulkiness. Complicated prisms are naturally more difficult and expensive to manufacture.

Magnification

Certain binoculars are designed to “zoom”, or adjust their magnification, to the degree desired by the user. This is performed by a mechanism which moves a portion of the ocular lens, either changing the direction or the size of incoming light and altering the image accordingly. The technology behind zoom lenses has still not reached its full potential, and zoom binoculars tend to lose focus or present double images as a result of the complexity of the various moving parts. Experts usually recommend the use of non-zoom binoculars for most activities.

All binoculars are issued a designation, such as 7 X 35, in which the first number indicates the degree of magnification (seven times, in this case) and the second indicates the diameter in millimeters of the objective lens. Binoculars are not designed to operate with high degrees of magnification because they are hand-held; the greater the magnification, the greater the wobbling of the image by routine shaking of the hands. Binoculars with magnifications greater than 10 times tend to be useless unless mounted. However, mounts contradict the purpose of binoculars as being portable and lightweight optical tools. High magnification can also result in the viewing of undesirable and distracting atmospheric effects, such as heat wave distortions.

Using Binoculars

Despite these limitations, binoculars can be used to surprising effect by observers of nature and amateur astronomers. Even a simple pair of binoculars trained on the night sky will reveal a variety of faint stars and distant star clusters that would be otherwise invisible to the naked eye.

By Matthew Ingalls




	Binoculars Binoculars are a tool used to magnify distant images. They consist of two small telescopes attached, side-by-side, to correspond with the length of the viewer's eyespan. The dual design allows the viewer to perceive objects in three dimensions, in contrast to a telescope, which distorts the depth of the image due to the limitations of viewing an object through a single eye. Binoculars possess the further advantage of being less bulky (and thus more portable) than telescopes, which routinely require a tripod or other heavy mount to operate. On average, binoculars are also far less expensive to produce. These advantages come at the expense of magnification power, which averages six to 10 times for an average pair. By contrast, a good backyard telescope can resolve anywhere from 20 to 60 times magnification. Binocular Lenses Binoculars operate on the same principle as eyeglasses, which use curved lenses to gather light to the eye in order to distort an image's apparent size. Binoculars make use of two lenses: the ocular lens, where the eye is placed, and the objective lens, found at the far end. Light is gathered into the objective lens and reflected back and forth by a series of prisms found in the tube itself, thereby increasing depth perception and allowing for the compact design of the binoculars themselves. Without such reflection, light would be required to traverse down a much larger tube to be enhanced. The more complex the prism, the more reflection that occurs, which in turn allows for a tube with less length and bulkiness. Complicated prisms are naturally more difficult and expensive to manufacture. Magnification Certain binoculars are designed to “zoom”, or adjust their magnification, to the degree desired by the user. This is performed by a mechanism which moves a portion of the ocular lens, either changing the direction or the size of incoming light and altering the image accordingly. The technology behind zoom lenses has still not reached its full potential, and zoom binoculars tend to lose focus or present double images as a result of the complexity of the various moving parts. Experts usually recommend the use of non-zoom binoculars for most activities. All binoculars are issued a designation, such as 7 X 35, in which the first number indicates the degree of magnification (seven times, in this case) and the second indicates the diameter in millimeters of the objective lens. Binoculars are not designed to operate with high degrees of magnification because they are hand-held; the greater the magnification, the greater the wobbling of the image by routine shaking of the hands. Binoculars with magnifications greater than 10 times tend to be useless unless mounted. However, mounts contradict the purpose of binoculars as being portable and lightweight optical tools. High magnification can also result in the viewing of undesirable and distracting atmospheric effects, such as heat wave distortions. Using Binoculars Despite these limitations, binoculars can be used to surprising effect by observers of nature and amateur astronomers. Even a simple pair of binoculars trained on the night sky will reveal a variety of faint stars and distant star clusters that would be otherwise invisible to the naked eye. By Matthew Ingalls Related Links: Binoculars Introduction to basic principles of binoculars.