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Lookout Mountain (Los Angeles County, California)
Lookout Mountain in Los Angeles County, California is a peak on the shoulder of Mount San Antonio ("Mount Baldy"). The peak was used by Albert A. Michelson to measure the speed of light in 1925–1929. To do so, a 21.5 mile baseline was established in 1923 by U.S. Coast and Geodetic Survey, with accuracy of 1 part in 11 million, in Pasadena at the base of Mount Baldy, roughly to Rancho Cucamonga at the base of Mount Wilson. It may have been the most accurate baseline ever determined, at the time. Coast and Geodetic Survey then used the baseline to triangulate the distance to the Mount Wilson Observatory, with distance error about 1 part in 5 million, and Michelson measured light travel time between the stations with a rotating mirror apparatus. The concrete piers on Lookout Mountain used for the Michelson observations still exist. The first fire lookout in the Angeles National Forest The Angeles National Forest (ANF) of the United States Forest Service, U.S. Forest Servic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles County, California
Los Angeles County, officially the County of Los Angeles, and sometimes abbreviated as L.A. County, is the List of the most populous counties in the United States, most populous county in the United States and in the U.S. state of California, with 9,861,224 residents estimated as of 2022. It is the most populous non–State (United States), state-level government entity in the United States. Its population is greater than that of 40 individual List of U.S. states and territories by population, U.S. states. At and with List of cities in Los Angeles County, California, 88 incorporated cities and List of unincorporated communities in Los Angeles County, California, many unincorporated areas, it is home to more than one-quarter of California residents and is one of the most ethnically diverse counties in the United States. Its county seat, Los Angeles, is also California's most populous city and the second-most populous city in the United States, with about 3.9 million residents. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount San Antonio
Mount San Antonio, commonly referred to as Mount Baldy or Old Baldy, is a summit in the San Gabriel Mountains on the border of Los Angeles and San Bernardino counties of California. Lying within the San Gabriel Mountains National Monument and Angeles National Forest, it is the high point of the range, the county, and the Los Angeles metropolitan area. Mount San Antonio's sometimes snow-capped peaks are visible on clear days and dominate the view of the Los Angeles Basin skyline. The peak and a subsidiary one to the west form a double summit of a steep-sided east–west ridge. The summit is accessible via a number of connecting ridges along hiking trails from the north, east, south, and southwest. Name The Tongva call the mountain ''Yoát'' or ''Joat'', which means ''snow'', and the Mohave call it ''Avii Kwatiinyam''. The name ''Mount San Antonio'' was probably bestowed by Antonio Maria Lugo, owner of a rancho near present-day Compton circa 1840, in honor of his patron saint, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert A
Albert may refer to: Companies * Albert (supermarket), a supermarket chain in the Czech Republic * Albert Heijn, a supermarket chain in the Netherlands * Albert Market, a street market in The Gambia * Albert Productions, a record label * Albert Computers, Inc., a computer manufacturer in the 1980s Entertainment * ''Albert'' (1985 film), a Czechoslovak film directed by František Vláčil * ''Albert'' (2015 film), a film by Karsten Kiilerich * ''Albert'' (2016 film), an American TV movie * ''Albert'' (Ed Hall album), 1988 * "Albert" (short story), by Leo Tolstoy * Albert (comics), a character in Marvel Comics * Albert (''Discworld''), a character in Terry Pratchett's ''Discworld'' series * Albert, a character in Dario Argento's 1977 film ''Suspiria'' Military * Battle of Albert (1914), a WWI battle at Albert, Somme, France * Battle of Albert (1916), a WWI battle at Albert, Somme, France * Battle of Albert (1918), a WWI battle at Albert, Somme, France People * Albert (given ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Of Light
The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space. All forms of electromagnetic radiation, including visible light, travel at the speed of light. For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and very sensitive measurements, their finite speed has noticeable effects. Starlight viewed on Earth left the stars many years ago, allowing humans to study the history of the universe by viewing distant objects. When communicating with distant space probes, it can take minutes to hours for signals to travel from Earth to the spacecraft and vice versa. In computing, the speed of light fixes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baseline (surveying)
In surveying, a baseline is a line between two points on the earth's surface and the direction and distance between them. In a triangulation network, at least one baseline between two stations needs to be measured to calculate the size of the triangles by trigonometry. In the United States Public Land Survey System, a baseline is the principal east-west line (i.e., a parallel) upon which all rectangular surveys in a defined area are based. The baseline meets its corresponding principal meridian at the point of origin, or '' initial point'', for the land survey. For example, the baseline for Nebraska and Kansas is shared as the border for both states, at the 40th parallel north. More specifically a baseline may be the line that divides a survey township between north and south. "Baseline Road" in the United States Many communities in the United States have roads that run along survey baselines, many of which are named to reflect that fact. Some examples: * In Little Rock, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Wilson (California)
Mount Wilson is a peak in the San Gabriel Mountains, located within the San Gabriel Mountains National Monument and Angeles National Forest in Los Angeles County, California. With only minor topographical prominence the peak is not naturally noticeable from a distance, although it is easily identifiable due to the large number of antennas near its summit. It is a subsidiary peak of nearby San Gabriel Peak. It is the location of the Mount Wilson Observatory, which is an important astronomical facility in Southern California with historic and telescopes, and and solar towers. The newer CHARA Array, run by Georgia State University, is also sited there and does important interferometric stellar research. The summit is at . While not the tallest peak in its vicinity, it is high enough in elevation that snow can sometimes interrupt astronomical activities on the mountain. All of the mountains south of the summit are far shorter leading to unobstructed views across the Los An ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points. Applications In surveying Specifically in surveying, triangulation involves only angle measurements at known points, rather than measuring distances to the point directly as in trilateration; the use of both angles and distance measurements is referred to as triangulateration. In computer vision Computer stereo vision and optical 3D measuring systems use this principle to determine the spatial dimensions and the geometry of an item. Basically, the configuration consists of two sensors observing the item. One of the sensors is typically a digital camera device, and the other one can also be a camera or a light projector. The projection centers of the sensors and the considered point on the object's surface define a (spatial) triangle. Within this triangle, the distance between the sensors is the base ''b'' and must be known. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Wilson Observatory
The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles. The observatory contains two historically important telescopes: the Hooker telescope, which was the largest aperture telescope in the world from its completion in 1917 to 1949, and the 60-inch telescope which was the largest operational telescope in the world when it was completed in 1908. It also contains the Snow solar telescope completed in 1905, the 60 foot (18 m) solar tower completed in 1908, the 150 foot (46 m) solar tower completed in 1912, and the CHARA array, built by Georgia State University, which became fully operational in 2004 and was the largest optical interferometer in the world at its completion. Due to the inversion layer that traps warm air and smog over Los Angeles, Mount Wilson has steadier air than any other location in Nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire Lookout
A fire lookout (partly also called a fire watcher) is a person assigned the duty to look for fire from atop a building known as a fire lookout tower. These towers are used in remote areas, normally on mountain tops with high elevation and a good view of the surrounding terrain, to spot smoke caused by a wildfire. Once a possible fire is spotted, "Smoke Reports", or "Lookout Shots" are relayed to the local Emergency Communications Center (ECC), often by radio or phone. A fire lookout can use a device known as an Osborne Fire Finder to obtain the radial in degrees off the tower, and the estimated distance from the tower to the fire. Part of the lookout's duties include taking weather readings and reporting the findings to the Emergency Communications Center throughout the day. Often several lookouts will overlap in coverage areas and each will “cross” the same smoke, allowing the ECC to use triangulation from the radials to achieve an accurate location of the fire. Onc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angeles National Forest
The Angeles National Forest (ANF) of the United States Forest Service, U.S. Forest Service is located in the San Gabriel Mountains and Sierra Pelona Mountains, primarily within Los Angeles County, California, Los Angeles County in southern California. The ANF manages a majority of the San Gabriel Mountains National Monument. The national forest was established in 1908, incorporating the first San Bernardino National Forest and parts of the former Santa Barbara National Forest, Santa Barbara and San Gabriel National Forests. Angeles National Forest headquarters are located in Arcadia, California. Geography The Angeles National Forest covers a total of , protecting large areas of the San Gabriel Mountains and Sierra Pelona Mountains. It is located just north of the densely inhabited metropolitan area of Greater Los Angeles Area, Greater Los Angeles. While primarily within Los Angeles County, a small part extends eastward into southwestern San Bernardino County, California, San Be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrangle (geography)
A "quadrangle" is a topographic map produced by the United States Geological Survey (USGS) covering the United States. The maps are usually named after local physiographic features. The shorthand "quad" is also used, especially with the name of the map; for example, "the Ranger Creek, Texas quad". From approximately 1947-1992, the USGS produced the 7.5 minute series, with each map covering an area one-quarter of the older 15-minute quad series, which it replaced. A 7.5 minute quadrangle map covers an area of . Both map series were produced via photogrammetric analysis of aerial photography using stereoplotters supplemented by field surveys. These maps employ the 1927 North American Datum (NAD27); conversion or a change in settings is necessary when using a GPS which by default employ the WGS84 geodetic datum. Beginning in 2009, the USGS made available digital versions of 7.5 minute quadrangle maps based on GIS data that use the NAD83 datum, which is typically within one meter of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
