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Surveyor III
Surveyor 3 was the third lander of the American uncrewed Surveyor program sent to explore the surface of the Moon in 1967. It was the first mission to carry a surface-soil sampling-scoop. Surveyor 3 was visited by Apollo 12 astronauts Pete Conrad and Alan Bean in November 1969, and remains the only probe visited by humans on another world. The Apollo 12 astronauts excised several components of Surveyor 3, including the television camera, and returned them to Earth for study. History Launched on April 17, 1967, Surveyor 3 landed on April 20, 1967, at the Mare Cognitum portion of the Oceanus Procellarum (S3° 01' 41.43" W23° 27' 29.55"), in a small crater that was subsequently named Surveyor. It transmitted 6,315 TV images to the Earth, including the first images to show what planet Earth looked like from the Moon's surface. As Surveyor 3 was landing in the crater highly reflective rocks confused the spacecraft's lunar descent radar. The engines failed to cut off at 14 feet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apollo 12
Apollo 12 (November 14–24, 1969) was the sixth crewed flight in the United States Apollo program and the second to land on the Moon. It was launched on November 14, 1969, by NASA from the Kennedy Space Center, Florida. Commander Pete Conrad, Charles "Pete" Conrad and Lunar Module Pilot Alan Bean, Alan L. Bean performed just over one day and seven hours of lunar surface activity while Command Module Pilot Richard F. Gordon Jr., Richard F. Gordon remained in lunar orbit. Apollo 12 would have attempted the first lunar landing had Apollo 11 failed, but after the success of Neil Armstrong's mission, Apollo 12 was postponed by two months, and other Apollo missions also put on a more relaxed schedule. More time was allotted for geologic training in preparation for Apollo 12 than for Apollo 11, Conrad and Bean making several geology field trips in preparation for their mission. Apollo 12's spacecraft and launch vehicle were almost identical to Apollo 11's. One addition was hammocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mare Cognitum
Mare Cognitum (Latin ''cognitum'', the "Sea that has Become Known") is a lunar mare located in a basin or large crater which sits in the second ring of Oceanus Procellarum. To the northwest of the mare is the Montes Riphaeus mountain range, part of the rim of the buried crater or basin containing the mare. Previously unnamed, the mare received its name in 1964 in reference to its selection as the target for the successful impact probe Ranger 7, the first American spacecraft to return closeup images of the Moon's surface. Origin The basin material is of the Pre-Nectarian epoch, while most of the basaltic mare material is of the Upper Imbrian epoch. Exploration The Ranger 7 lunar probe impacted Mare Cognitum at the conclusion of its picture-taking mission. Surveyor 3 and Apollo 12 landed near its northern shore. The outcrop of the Fra Mauro formation, where Apollo 14 landed, is also located near Mare Cognitum. Statio Cognitum On November 19, 1969, astronauts Pete Conrad and Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azimuth
An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematically, the relative position vector from an observer (origin) to a point of interest is projected perpendicularly onto a reference plane (the horizontal plane); the angle between the projected vector and a reference vector on the reference plane is called the azimuth. When used as a celestial coordinate, the azimuth is the horizontal direction of a star or other astronomical object in the sky. The star is the point of interest, the reference plane is the local area (e.g. a circular area with a 5 km radius at sea level) around an observer on Earth's surface, and the reference vector points to true north. The azimuth is the angle between the north vector and the star's vector on the horizontal plane. Azimuth is usually measured in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diaphragm (optics)
In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to ''stop'' the passage of light, except for the light passing through the ''aperture''. Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses). The diaphragm is placed in the light path of a lens or objective, and the size of the aperture regulates the amount of light that passes through the lens. The centre of the diaphragm's aperture coincides with the optical axis of the lens system. Most modern cameras use a type of adjustable diaphragm known as an iris diaphragm, and often referred to simply as an iris. See the articles on aperture and f-number for the photographic effect and system of quantification of varying the opening in the diaphragm. Iris diaphragms versus other types A natural optical system that has a diaphragm an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter (optics)
An optical filter is a device that selectively transmits light of different wavelengths, usually implemented as a glass plane or plastic device in the optical path, which are either dyed in the bulk or have interference coatings. The optical properties of filters are completely described by their frequency response, which specifies how the magnitude and phase of each frequency component of an incoming signal is modified by the filter. Filters mostly belong to one of two categories. The simplest, physically, is the absorptive filter; then there are interference or dichroic filters. Many optical filters are used for optical imaging and are manufactured to be transparent; some used for light sources can be translucent. Optical filters selectively transmit light in a particular range of wavelengths, that is, colours, while absorbing the remainder. They can usually pass long wavelengths only (longpass), short wavelengths only (shortpass), or a band of wavelengths, blocking both l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shutter (photography)
In photography, a shutter is a device that allows light to pass for a determined period, exposing photographic film or a photosensitive digital sensor to light in order to capture a permanent image of a scene. A shutter can also be used to allow pulses of light to pass outwards, as seen in a movie projector or a signal lamp. A shutter of variable speed is used to control exposure time of the film. The shutter is constructed so that it automatically closes after a certain required time interval. The speed of the shutter is controlled by a ring outside the camera, on which various timings are marked. Camera shutter Camera shutters can be fitted in several positions: * Leaf shutters are usually fitted within a lens assembly (''central shutter''), or more rarely immediately behind (''behind-the-lens shutter'') or, even more rarely, in front of a lens, and shut off the beam of light where it is narrow. *Focal-plane shutters are mounted near the focal plane and move to uncover the fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower opti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vidicon
Video camera tubes were devices based on the cathode ray tube that were used in television cameras to capture television images, prior to the introduction of charge-coupled device (CCD) image sensors in the 1980s. Several different types of tubes were in use from the early 1930s, and as late as the 1990s. In these tubes, an cathode ray, electron beam was scanned across an image of the scene to be broadcast focused on a target. This generated a current that was dependent on the brightness of the image on the target at the scan point. The size of the striking ray was tiny compared to the size of the target, allowing 483 horizontal scan lines per image in the NTSC format, 576 lines in PAL, and as many as 1035 lines in Multiple sub-Nyquist sampling encoding, Hi-Vision. Cathode ray tube Any vacuum tube which operates using a focused beam of electrons, originally called cathode rays, is known as a cathode ray tube (CRT). These are usually seen as display devices as used in older (i.e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space
Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as spacetime. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. Debates concerning the nature, essence and the mode of existence of space date back to antiquity; namely, to treatises like the ''Timaeus'' of Plato, or Socrates in his reflections on what the Greeks called ''khôra'' (i.e. "space"), or in the ''Physics'' of Aristotle (Book IV, Delta) in the definition of ''topos'' (i.e. place), or in the later "geometrical conception of place" as "spac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surveyor 1
Surveyor 1 was the first lunar soft-lander in the uncrewed Surveyor program of the National Aeronautics and Space Administration (NASA, United States). This lunar soft-lander gathered data about the lunar surface that would be needed for the crewed Apollo Moon landings that began in 1969. The successful soft landing of Surveyor 1 on the '' Ocean of Storms'' was the first by an American space probe on any extraterrestrial body, occurring on the first attempt and just four months after the first soft Moon landing by the Soviet Union's Luna 9 probe. Surveyor 1 was launched May 30, 1966, from the Cape Canaveral Air Force Station at Cape Canaveral, Florida, and it landed on the Moon on June 2, 1966. Surveyor 1 transmitted 11,237 still photos of the lunar surface to the Earth by using a television camera and a sophisticated radio-telemetry system. The Surveyor program was managed by the Jet Propulsion Laboratory, in Los Angeles County, California, and the Surveyor space probe was bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II. A key development was the cavity magnetron in the United Kingdom, which allowed the creation of relatively small systems with sub-meter resolution. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
