Binoculars in the context of "Depth perception"

A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis. Lenses are made from materials such as glass or plastic and are ground, polished, or molded to the required shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called "lenses", such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses.

Lenses are used in various imaging devices such as telescopes, binoculars, and cameras. They are also used as visual aids in glasses to correct defects of vision such as myopia and hypermetropia.

Leica Camera AG (/ˈlaɪkə/) is a German company that manufactures cameras, optical lenses, photographic lenses, binoculars, and rifle scopes. The company was founded by Ernst Leitz in 1869 (Ernst Leitz Wetzlar), in Wetzlar, Germany. The name Leica is derived from the first three letters of the founder's surname (Leitz) and the first two of the word camera: lei-ca (LEItz CAmera).

In 1986, the Leitz company changed its name to Leica and moved its factory from Wetzlar to the nearby town of Solms.

The Pipe Nebula (also known as Barnard 59, 65–67, and 78) is a dark nebula in the Ophiuchus constellation and a part of the Dark Horse Nebula. It is a large but readily apparent smoking pipe-shaped dust lane that obscures the Milky Way star clouds behind it. Clearly visible to the naked eye in the Southern United States under clear dark skies, but it is best viewed with 7× binoculars.

The nebula has two main parts: the Pipe Stem with an opacity of 6 which is composed of Barnard 59, 65, 66, and 67 (also known as LDN 1773) 300′ x 60′ RA: 17 21 Dec: −27° 23′; and the Bowl of the Pipe with an opacity of 5 which is composed of Barnard 78 (also known as LDN 42) 200′ x 140′ RA: 17 33 Dec: −26° 30′.

The Galilean moons (/ˌɡælɪˈleɪ.ən/), or Galilean satellites, are the four largest moons of Jupiter. They are, in descending-size order, Ganymede, Callisto, Io, and Europa. They are the most readily visible Solar System objects after Saturn, the dimmest of the classical planets; though their closeness to bright Jupiter makes naked-eye observation very difficult, they are readily seen with common binoculars, even under night sky conditions of high light pollution. The invention of the telescope allowed astronomers to discover the moons in 1610. Through this, they became the first Solar System objects discovered since humans have started tracking the classical planets, and the first objects to be found to orbit any planet beyond Earth.

They are planetary-mass moons and among the largest objects in the Solar System. All four, along with Titan, Triton, and Earth's Moon, are larger than any of the Solar System's dwarf planets. The largest, Ganymede, is the largest moon in the Solar System and surpasses the planet Mercury in size (though not mass). Callisto is only slightly smaller than Mercury in size; the smaller ones, Io and Europa, are about the size of the Moon. The three inner moons — Io, Europa, and Ganymede — are in a 4:2:1 orbital resonance with each other. While the Galilean moons are spherical, all of Jupiter's remaining moons have irregular forms because they are too small for their self-gravitation to pull them into spheres.

Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, some amateur astronomers make contributions in doing citizen science, such as by monitoring variable stars, double stars, sunspots, or occultations of stars by the Moon or asteroids, or by discovering transient astronomical events, such as comets, galactic novae or supernovae in other galaxies.

Amateur astronomers do not use the field of astronomy as their primary source of income or support, and usually have no professional degree in astrophysics or advanced academic training in the subject. Most amateurs are hobbyists, while others have a high degree of experience in astronomy and may often assist and work alongside professional astronomers. Many astronomers have studied the sky throughout history in an amateur framework; however, since the beginning of the twentieth century, professional astronomy has become an activity clearly distinguished from amateur astronomy and associated activities.

In optical engineering, an objective is an optical element that gathers light from an object being observed and focuses the light rays from it to produce a real image of the object. Objectives can be a single lens or mirror, or combinations of several optical elements. They are used in microscopes, binoculars, telescopes, cameras, slide projectors, CD players and many other optical instruments. Objectives are also called object lenses, object glasses, or objective glasses.

A monopod, also called a unipod, is a single staff or pole used to help support cameras, binoculars, rifles or other precision instruments in the field.