1.
Lowell Observatory
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Lowell Observatory is an astronomical observatory in Flagstaff, Arizona, United States. Lowell Observatory was established in 1894, placing it among the oldest observatories in the United States, in 2011, the Observatory was named one of The Worlds 100 Most Important Places by TIME. It was at the Lowell Observatory that the dwarf planet Pluto was discovered in 1930 by Clyde Tombaugh, the Observatorys original 61-centimeter Alvan Clark & Sons Telescope is still in use today for public education. It was founded by astronomer Percival Lowell of Bostons well-known Lowell family and is overseen by a sole trustee, the first trustee was Lowells third cousin Guy Lowell. Percivals nephew Roger Putnam served from 1927–1967, followed by Rogers son Michael, Michaels brother William Lowell Putnam III, the observatory operates several telescopes at three locations in the Flagstaff area. The telescope, built in 1896 for $20,000, was assembled in Boston by Alvan Clark & Sons, also located on the Mars Hill campus is the 33-centimeter Pluto Discovery Telescope, used by Clyde Tombaugh in 1930 to discover the dwarf planet Pluto. Lowell is a partner with the United States Naval Observatory and Naval Research Laboratory in the Navy Precision Optical Interferometer also located at that site, the Observatory also operates smaller research telescopes at its historic site on Mars Hill and in Australia and Chile. Past Anderson Mesa, on the peak of Happy Jack, Lowell Observatory has also built and is commissioning the 4. 28-meter Discovery Channel Telescope in partnership with Discovery Communications, Inc. Aside from the array of research and discoveries listed below. When Harold L. Johnson took over as the director in 1952, in 1953, the current 53 cm telescope was erected. Beginning in 1954, this telescope began monitoring the brightness of two planets, and comparing these measurements with a reference set of sunlike stars. Lowell Observatory is building a major new reflecting telescope in partnership with Discovery Communications, located near Happy Jack, the primary mirror of the Discovery Channel Telescope will be 4.28 m in diameter. It will be notable for its uncommon meniscus design for such a large mirror. This mirror was ground and polished into its parabolic shape at the Optical Fabrication, Lowell Observatorys astronomers conduct research on a wide range of solar system and astrophysical topics using ground-based, airborne, and space-based telescopes. In addition, the Observatory staff designs and builds custom instrumentation for use on Lowells telescopes, for example, Lowell staff built a sophisticated high-speed camera for use on the Stratospheric Observatory for Infrared Astronomy. SOFIA is a joint project of the United States and German space agencies, Lowell, Percival, Pickering, W. H. and the founding of the Lowell Observatory. National Historic Landmarks Program, Lowell Observatory+ Historic American Buildings Survey No, aZ-206, Lowell Observatory,1400 West Mars Hill Road, Flagstaff, Coconino County, AZ HABS No. AZ-206-A, Lowell Observatory, Slipher Building HABS No, aZ-206-B, Lowell Observatory, Clark Dome HABS No
2.
United States Naval Observatory
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The USNO operates the Master Clock, which provides precise time to the GPS satellite constellation run by the United States Air Force. The USNO performs radio VLBI-based positions of quasars with numerous global collaborators, aside from its scientific mission, a house located within the Naval Observatory complex serves as the official residence of the Vice President of the United States. President John Quincy Adams, who in 1825 signed the bill for the creation of an observatory just before leaving presidential office, had intended for it to be called the National Observatory. The names National Observatory and Naval Observatory were both used for 10 years, until a ruling was passed to use the latter. Adams had made protracted efforts to bring astronomy to a level at that time. He spent many nights at the observatory, watching and charting the stars, established by the order of the United States Secretary of the Navy John Branch on 6 December 1830 as the Depot of Charts and Instruments, the Observatory rose from humble beginnings. Placed under the command of Lieutenant Louis M. Goldsborough, with an budget of $330, its primary function was the restoration, repair. It was made into an observatory in 1842 via a federal law. Lieutenant James Melville Gilliss was put in charge of obtaining the instruments needed, lt. Gilliss visited the principal observatories of Europe with the mission to purchase telescopes and scientific devices and books. The observatorys primary mission was to care for the United States Navys marine chronometers, charts and it calibrated ships chronometers by timing the transit of stars across the meridian. These facilities were listed on the National Register of Historic Places in 2017, the first superintendent was Navy Commander Matthew Fontaine Maury. Maury had the worlds first vulcanized time ball, created to his specifications by Charles Goodyear for the U. S. Observatory and it was the first time ball in the United States, being placed into service in 1845, and the 12th in the world. Maury kept accurate time by the stars and planets, the time ball was dropped every day except Sunday precisely at the astronomically defined moment of Mean Solar Noon, enabling all ships and civilians to know the exact time. Time was also sold to the railroads and was used in conjunction with railroad chronometers to schedule American rail transport, early in the 20th century, the Arlington Time Signal broadcast this service to wireless receivers. In 1849 the Nautical Almanac Office was established in Cambridge, Massachusetts as a separate organization and it was moved to Washington, D. C. in 1866, colocating with the U. S. Naval Observatory in 1893. On September 20,1894, the NAO became a branch of USNO, the astronomical measurements taken of the transit of Venus by a number of countries since 1639 resulted in a progressively more accurate definition of the AU. Relying heavily on methods, the naval observers returned 350 photographic plates in 1874. This calculated distance was a significant improvement over several previous estimates, the telescope used for the discovery of the Moons of Mars was the 26-inch refractor, then located at Foggy Bottom
3.
Coconino County, Arizona
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Coconino County is a county located in the north central part of the U. S. state of Arizona. The population was 134,421 at the 2010 census, the county takes its name from Cohonino, a name applied to the Havasupai. It is the second-largest county by area in the contiguous United States, behind San Bernardino County, California, Coconino County comprises the Flagstaff, AZ Metropolitan Statistical Area. Coconino County contains Grand Canyon National Park, the Havasupai Nation, and parts of the Navajo Nation, Hualapai Nation, and Hopi Nation. It has a relatively large Native American population at nearly 30% of the total population, being mostly Navajo with smaller numbers of Havasupai, Hopi. The county was the setting for George Herrimans early-20th-century Krazy Kat comic strip, after the building of the Atlantic & Pacific Railroad in 1883 the region of northern Yavapai County began experiencing rapid growth. The people of the northern reaches had tired of the rigors of travelling all the way to Prescott for county business and they also believed that they were a significant enough entity that they should have their own county jurisdiction. Therefore, they decided in 1887 to petition for secession from Yavapai and they remained part of Yavapai, however, until 1891 when Coconino County was formed and its seat declared to be Flagstaff. According to the U. S. Census Bureau, the county has an area of 18,661 square miles. It is the largest county by area in Arizona and the second-largest county in the United States after San Bernardino County in California. It has more area than each of the following U. S. states, Connecticut, Delaware, Hawaii, Maryland, Massachusetts, New Hampshire, New Jersey, Rhode Island. The highest natural point in the county, as well as the state, is Humphreys Peak at 12,637 feet or 3,852 metres. The Barringer Meteor Crater is located in Coconino County, the Havasupai Reservation is the only one that lies entirely within the countys borders. As of the 2000 census, there were 116,320 people,40,448 households, the population density was 6 people per square mile. There were 53,443 housing units at a density of 3 per square mile. 10. 94% of the population were Hispanic or Latino of any race,18. 59% reported speaking Navajo at home, while 6. 58% speak Spanish. 22. 10% of all households were made up of individuals and 4. 50% had someone living alone who was 65 years of age or older, the average household size was 2.80 and the average family size was 3.36. In the county, the population was out with 28. 70% under the age of 18,14. 40% from 18 to 24,29. 20% from 25 to 44,20. 70% from 45 to 64
4.
Flagstaff, Arizona
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Flagstaff is a city in northern Arizona, in the southwestern United States. In 2015, the estimated population was 70,320. Flagstaffs combined metropolitan area has an population of 139,097. It is the county seat of Coconino County, the city is named after a ponderosa pine flagpole made by a scouting party from Boston to celebrate the United States Centennial on July 4,1876. Flagstaff lies near the edge of the Colorado Plateau, along the western side of the largest contiguous Ponderosa Pine forest in the continental United States. Flagstaff is located adjacent to Mount Elden, just south of the San Francisco Peaks, humphreys Peak, the highest point in Arizona at 12,633 feet, is located about 10 miles north of Flagstaff in Kachina Peaks Wilderness. Flagstaffs early economy was based on the lumber, railroad, Flagstaff has a strong tourism sector, due to its proximity to Grand Canyon National Park, Oak Creek Canyon, the Arizona Snowbowl, Meteor Crater, and historic Route 66. The city is also a center for medical device manufacturing, since Flagstaff is home to W. L. Gore, there exist several stories and legends regarding the origin of the citys name. It is said that, because of the flag that was raised, the first permanent settlement was in 1876, when Thomas F. McMillan built a cabin at the base of Mars Hill on the west side of town. During the 1880s, Flagstaff began to grow, opening its first post office, the early economy was based on timber, sheep, and cattle. By 1886, Flagstaff was the largest city on the line between Albuquerque and the west coast of the United States. A circa 1900 diary entry by journalist Sharlot Hall described the houses in the city at the time as a third rate mining camp, with unkempt air, in 1894, Massachusetts astronomer Percival Lowell hired A. E. Douglass to scout an ideal site for a new observatory. Douglass, impressed by Flagstaffs elevation, named it as a location for the now famous Lowell Observatory, saying, other things being equal. Two years later, the specially designed 24-inch Clark telescope that Lowell had ordered was installed, in 1930, Pluto was discovered using one of the observatorys telescopes. During the Apollo program in the 1960s, the Clark Telescope was used to map the moon for the lunar expeditions, in homage to the citys importance in the field of astronomy, asteroid 2118 Flagstaff is named for the city, and 6582 Flagsymphony for the Flagstaff Symphony Orchestra. The Northern Arizona Normal School was established in 1899, renamed Northern Arizona University in 1966, Flagstaffs cultural history received a significant boost on April 11,1899, when the Flagstaff Symphony made its concert debut at Babbitts Opera House. The orchestra continues today as the Flagstaff Symphony Orchestra, with its venue at the Ardrey Auditorium on the campus of Northern Arizona University. The city grew rapidly, primarily attributable to its location along the east–west transcontinental railroad line in the United States, in the 1880s, the railroads purchased land in the west from the federal government, which was then sold to individuals to help finance the railroad projects
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Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
6.
Cassegrain reflector
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The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas. Alternatively, as in radio telescopes, the final focus may be in front of the primary. In an asymmetrical Cassegrain, the mirror may be tilted to avoid obscuration of the primary or to avoid the need for a hole in the primary mirror, the classic Cassegrain configuration uses a parabolic reflector as the primary while the secondary mirror is hyperbolic. Modern variants often have a primary for increased performance, or the primary and/or secondary are spherical or elliptical for ease of manufacturing. The Cassegrain reflector is named after a published reflecting telescope design that appeared in the April 25,1672 Journal des sçavans which has been attributed to Laurent Cassegrain. Similar designs using convex secondaries have been found in the Bonaventura Cavalieris 1632 writings describing burning mirrors, james Gregorys 1662 attempts to create a reflecting telescope included a Cassegrain configuration, judging by a convex secondary mirror found among his experiments. The Cassegrain design is used in catadioptric systems. The Classic Cassegrain has a primary mirror, and a hyperbolic secondary mirror that reflects the light back down through a hole in the primary. Folding the optics makes this a compact design, on smaller telescopes, and camera lenses, the secondary is often mounted on an optically flat, optically clear glass plate that closes the telescope tube. This support eliminates the diffraction effects caused by a straight-vaned support spider. The closed tube stays clean, and the primary is protected and it makes use of the special properties of parabolic and hyperbolic reflectors. A concave parabolic reflector will reflect all incoming light rays parallel to its axis of symmetry to a single point, a convex hyperbolic reflector has two foci and will reflect all light rays directed at one of its two foci towards its other focus. The parabolic mirror reflects parallel light rays entering the telescope to its focus, the hyperbolic mirror then reflects those light rays to its other focus, where the image is observed. The Ritchey-Chrétien is a specialized Cassegrain reflector which has two hyperbolic mirrors and it is free of coma and spherical aberration at a flat focal plane, making it well suited for wide field and photographic observations. It was invented by George Willis Ritchey and Henri Chrétien in the early 1910s and this design is very common in large professional research telescopes, including the Hubble Space Telescope, Keck Telescopes and VLT telescope, it is also found in high-grade amateur telescopes. Ingalls, the astronomy editor at the time. It uses a concave primary mirror and a convex spherical secondary. While this system is easier to polish than a classic Cassegrain or Ritchey-Chretien system, because this is less noticeable at longer focal ratios, Dall-Kirkhams are seldom faster than f/15
7.
Telescope
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A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation. The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s and they found use in both terrestrial applications and astronomy. Within a few decades, the telescope was invented, which used mirrors to collect. In the 20th century many new types of telescopes were invented, including radio telescopes in the 1930s, the word telescope now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The word telescope was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galileis instruments presented at a banquet at the Accademia dei Lincei, in the Starry Messenger, Galileo had used the term perspicillum. The earliest recorded working telescopes were the telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals, Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, Galileo heard about the Dutch telescope in June 1609, built his own within a month, and improved upon the design in the following year. Also in 1609, Thomas Harriot became the first person known to point a telescope skyward in order to make observations of a celestial object. The idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors—reduction of spherical aberration and no chromatic aberration—led to many proposed designs, in 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector. The invention of the lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter. The largest reflecting telescopes currently have objectives larger than 10 m, the 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays. The first purpose built radio telescope went into operation in 1937, since then, a tremendous variety of complex astronomical instruments have been developed. The name telescope covers a range of instruments. Most detect electromagnetic radiation, but there are differences in how astronomers must go about collecting light in different frequency bands. The near-infrared can be collected much like light, however in the far-infrared and submillimetre range. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm to 2000 μm, on the other hand, the Spitzer Space Telescope, observing from about 3 μm to 180 μm uses a mirror. Also using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe in the range from about 0.2 μm to 1.7 μm
8.
Reflecting telescope
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A reflecting telescope is an optical telescope which uses a single or combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century as an alternative to the telescope which. Although reflecting telescopes produce other types of aberrations, it is a design that allows for very large diameter objectives. Almost all of the telescopes used in astronomy research are reflectors. Reflecting telescopes come in many variations and may employ extra optical elements to improve image quality or place the image in a mechanically advantageous position. Since reflecting telescopes use mirrors, the design is referred to as a catoptric telescope. The idea that curved mirrors behave like lenses dates back at least to Alhazens 11th century treatise on optics, the potential advantages of using parabolic mirrors, primarily reduction of spherical aberration with no chromatic aberration, led to many proposed designs for reflecting telescopes. The most notable being James Gregory, who published a design for a ‘reflecting’ telescope in 1663. It would be ten years, before the experimental scientist Robert Hooke was able to build this type of telescope, Isaac Newton has been generally credited with building the first reflecting telescope in 1668. It used a spherically ground metal primary mirror and a diagonal mirror in an optical configuration that has come to be known as the Newtonian telescope. A curved primary mirror is the reflector telescopes basic optical element that creates an image at the focal plane, the distance from the mirror to the focal plane is called the focal length. The primary mirror in most modern telescopes is composed of a glass cylinder whose front surface has been ground to a spherical or parabolic shape. A thin layer of aluminum is deposited onto the mirror. Some telescopes use primary mirrors which are made differently, molten glass is rotated to make its surface paraboloidal, and is kept rotating while it cools and solidifies. The resulting mirror shape approximates a desired paraboloid shape that requires grinding and polishing to reach the exact figure needed. Reflecting telescopes, just like any other system, do not produce perfect images. The use of mirrors avoids chromatic aberration but they produce other types of aberrations, to avoid this problem most reflecting telescopes use parabolic shaped mirrors, a shape that can focus all the light to a common focus. Field curvature - The best image plane is in general curved and it is sometimes corrected by a field flattening lens
9.
Navy Precision Optical Interferometer
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The facility is located at Lowells Anderson Mesa Station on Anderson Mesa about 25 kilometers southeast of Flagstaff, Arizona. Until November 2011, the facility was known as the Navy Prototype Optical Interferometer, the NPOI project was initiated by the United States Naval Observatory in 1987. Lowell joined the project the year when the USNO decided to build the NPOI at Anderson Mesa. The first phase of construction was completed in 1994, which allowed the interferometer to see its first fringes, or light combined from multiple sources, the Navy began regular science operations in 1997. The NPOI has been upgraded and expanded since then, and has been operational for a decade. The workings of NPOI as an interferometer, are described at Scholarpedia. The NPOI is an astronomical interferometer laid out in a three-arm Y configuration, there are two types of stations that can be used in the NPOI. Astrometric stations, used to measure the positions of celestial objects very accurately, are fixed units placed 21 meters apart, with one on each arm and one at the center. Imaging stations can be moved to one of nine positions on each arm, light from either type of station is first directed into the feed system, which consists of long pipes which have been evacuated of all air. They lead to a switchyard of mirrors, where the light is directed into the six Long Delay Lines, the light is then sent into the Beam Combining Facility, where it enters the Fast Delay Lines. This third set of evacuated pipes contains mechanisms that move mirrors back and these compensate for the movement of the mirrors as they track an object across the sky, and for other effects. Finally, the leaves the pipes inside the BCF and goes to the Beam Combining Table. Both types of station have three elements, a siderostat, a Wide Angle Star Acquisition camera, and a Narrow Angle Tracking camera, the first is a precisely-ground flat mirror 50 cm in diameter. The WASA cameras control the aiming of the mirror at the celestial target, the reflected light from the siderostat is directed through a telescope which narrows the beam down to the diameter of the pipes, which is 12 cm. The light then hits the mirror of the NAT, which compensates for atmospheric effects and directs the light into the feed system. They were originally intended to be outrigger telescopes for the W. M. Keck Observatory in Hawaii, three telescopes are being prepared for near-immediate installation, while the fourth is currently at Mount Stromlo Observatory in Australia and will be incorporated at some point in the future. The new telescopes will help with faint object imaging and improved absolute astrometry, NOFS operates and leads the science for the Navy Precision Optical Interferometer, as noted, in collaboration with Lowell Observatory and the Naval Research Laboratory at Anderson Mesa. NOFS funds all principal operations, and from this contracts Lowell Observatory to maintain the Anderson Mesa facility, when complete by 2013, NPOI will run the longest baseline interferometer in the world
10.
Interferometry
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Interferometry is a family of techniques in which waves, usually electromagnetic waves, are superimposed causing the phenomenon of interference in order to extract information. Interferometers are widely used in science and industry for the measurement of small displacements, refractive index changes, in an interferometer, light from a single source is split into two beams that travel different optical paths, then combined again to produce interference. The resulting interference fringes give information about the difference in path length, waves which are not completely in phase nor completely out of phase will have an intermediate intensity pattern, which can be used to determine their relative phase difference. Most interferometers use light or some form of electromagnetic wave. Typically a single incoming beam of coherent light will be split into two beams by a beam splitter. Each of these beams travels a different route, called a path, the path difference, the difference in the distance traveled by each beam, creates a phase difference between them. It is this phase difference that creates the interference pattern between the initially identical waves. If a single beam has been split along two paths, then the difference is diagnostic of anything that changes the phase along the paths. This could be a change in the path length itself or a change in the refractive index along the path. As seen in Fig. 2a and 2b, the observer has a view of mirror M1 seen through the beam splitter. The fringes can be interpreted as the result of interference between light coming from the two virtual images S1 and S2 of the original source S, the characteristics of the interference pattern depend on the nature of the light source and the precise orientation of the mirrors and beam splitter. In Fig. 2a, the elements are oriented so that S1 and S2 are in line with the observer. Use of white light will result in a pattern of colored fringes, the central fringe representing equal path length may be light or dark depending on the number of phase inversions experienced by the two beams as they traverse the optical system. Interferometers and interferometric techniques may be categorized by a variety of criteria, In homodyne detection, the phase difference between the two beams results in a change in the intensity of the light on the detector. The resulting intensity of the light after mixing of two beams is measured, or the pattern of interference fringes is viewed or recorded. Most of the interferometers discussed in this article fall into this category, the heterodyne technique is used for shifting an input signal into a new frequency range as well as amplifying a weak input signal. A weak input signal of frequency f1 is mixed with a reference frequency f2 from a local oscillator. The nonlinear combination of the input signals creates two new signals, one at the sum f1 + f2 of the two frequencies, and the other at the difference f1 − f2 and these new frequencies are called heterodynes
11.
Astronomy
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Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry, in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, moons, stars, galaxies, and comets, while the phenomena include supernovae explosions, gamma ray bursts, more generally, all astronomical phenomena that originate outside Earths atmosphere are within the purview of astronomy. A related but distinct subject, physical cosmology, is concerned with the study of the Universe as a whole, Astronomy is the oldest of the natural sciences. The early civilizations in recorded history, such as the Babylonians, Greeks, Indians, Egyptians, Nubians, Iranians, Chinese, during the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the results and observations being used to confirm theoretical results. Astronomy is one of the few sciences where amateurs can play an active role, especially in the discovery. Amateur astronomers have made and contributed to many important astronomical discoveries, Astronomy means law of the stars. Astronomy should not be confused with astrology, the system which claims that human affairs are correlated with the positions of celestial objects. Although the two share a common origin, they are now entirely distinct. Generally, either the term astronomy or astrophysics may be used to refer to this subject, however, since most modern astronomical research deals with subjects related to physics, modern astronomy could actually be called astrophysics. Few fields, such as astrometry, are purely astronomy rather than also astrophysics, some titles of the leading scientific journals in this field includeThe Astronomical Journal, The Astrophysical Journal and Astronomy and Astrophysics. In early times, astronomy only comprised the observation and predictions of the motions of objects visible to the naked eye, in some locations, early cultures assembled massive artifacts that possibly had some astronomical purpose. Before tools such as the telescope were invented, early study of the stars was conducted using the naked eye, most of early astronomy actually consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, and the nature of the Sun, Moon, the Earth was believed to be the center of the Universe with the Sun, the Moon and the stars rotating around it. This is known as the model of the Universe, or the Ptolemaic system. The Babylonians discovered that lunar eclipses recurred in a cycle known as a saros
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Observatory
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An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed, historically, observatories were as simple as containing an astronomical sextant or Stonehenge. Astronomical observatories are mainly divided into four categories, space based, airborne, ground based, ground-based observatories, located on the surface of Earth, are used to make observations in the radio and visible light portions of the electromagnetic spectrum. Most optical telescopes are housed within a dome or similar structure, Telescope domes have a slit or other opening in the roof that can be opened during observing, and closed when the telescope is not in use. In most cases, the upper portion of the telescope dome can be rotated to allow the instrument to observe different sections of the night sky. Radio telescopes usually do not have domes, for optical telescopes, most ground-based observatories are located far from major centers of population, to avoid the effects of light pollution. The ideal locations for modern observatories are sites that have dark skies, a percentage of clear nights per year, dry air. At high elevations, the Earths atmosphere is thinner, thereby minimizing the effects of atmospheric turbulence, sites that meet the above criteria for modern observatories include the southwestern United States, Hawaii, Canary Islands, the Andes, and high mountains in Mexico such as Sierra Negra. Major optical observatories include Mauna Kea Observatory and Kitt Peak National Observatory in the USA, Roque de los Muchachos Observatory in Spain, and Paranal Observatory in Chile. Specific research study performed in 2009 shows that the best possible location for ground-based observatory on Earth is Ridge A — a place in the part of Eastern Antarctica. This location provides the least atmospheric disturbances and best visibility, beginning in 1930s, radio telescopes have been built for use in the field of radio astronomy to observe the Universe in the radio portion of the electromagnetic spectrum. Since the mid-20th century, a number of observatories have been constructed at very high altitudes, above 4. The largest and most notable of these is the Mauna Kea Observatory, the Chacaltaya Astrophysical Observatory in Bolivia, at 5,230 m, was the worlds highest permanent astronomical observatory from the time of its construction during the 1940s until 2009. It has now surpassed by the new University of Tokyo Atacama Observatory. As a result, the resolution of space telescopes such as the Hubble Space Telescope is often much smaller than a ground-based telescope with a similar aperture. However, all these advantages do come with a price, Space telescopes are much more expensive to build than ground-based telescopes. Due to their location, space telescopes are also difficult to maintain. The Hubble Space Telescope was serviced by the Space Shuttle while many other space telescopes cannot be serviced at all, Airborne observatories have the advantage of height over ground installations, putting them above most of the Earths atmosphere
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Light pollution
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Light pollution, also known as photopollution, is excessive, misdirected or obtrusive artificial light. As a major side-effect of urbanization, it is blamed for compromising health, disrupting ecosystems, Light pollution is the adding-of/added light itself, in analogy to added sound, carbon dioxide, etc. Adverse consequences are multiple, some of them may not be known yet, scientific definitions thus include the following, The degradation of photic habitat by artificial light. The alteration of light levels in the outdoor environment owing to artificial light sources. The alteration of light levels in the environment due to man-made sources of light. Indoor light pollution is such alteration of light levels in the environment due to sources of light. The introduction by humans, directly or indirectly, of light into the environment. The first three of the four scientific definitions describe the state of the environment. The fourth one describes the process of polluting by light, Light pollution is a side effect of industrial civilization. Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, since the early 1980s, a global dark-sky movement has emerged, with concerned people campaigning to reduce the amount of light pollution. The International Dark-Sky Association is one non-profit advocacy group involved in this movement, several industry groups also recognize light pollution as an important issue. For example, the Institution of Lighting Engineers in the United Kingdom provides its members with information about light pollution, the problems it causes, and how to reduce its impact. Since not everyone is irritated by the same lighting sources, it is common for one persons light pollution to be light that is desirable for another. One example of this is found in advertising, when an advertiser wishes for particular lights to be bright and visible, other types of light pollution are more certain. For instance, light that crosses a property boundary and annoys a neighbor is generally wasted. Where objective measurement is desired, light levels can be quantified by field measurement or mathematical modeling, authorities have also taken a variety of measures for dealing with light pollution, depending on the interests, beliefs and understandings of the society involved. Measures range from doing nothing at all, to implementing strict laws, Light pollution is a broad term that refers to multiple problems, all of which are caused by inefficient, unappealing, or unnecessary use of artificial light. Specific categories of light pollution include light trespass, over-illumination, glare, light clutter, a single offending light source often falls into more than one of these categories
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Arizona
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Arizona is a state in the southwestern region of the United States. It is also part of the Western United States and the Mountain West states and it is the sixth largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix, Arizona is one of the Four Corners states. It has borders with New Mexico, Utah, Nevada, California, and Mexico, Arizonas border with Mexico is 389 miles long, on the northern border of the Mexican states of Sonora and Baja California. Arizona is the 48th state and last of the states to be admitted to the Union. Historically part of the territory of Alta California in New Spain, after being defeated in the Mexican–American War, Mexico ceded much of this territory to the United States in 1848. The southernmost portion of the state was acquired in 1853 through the Gadsden Purchase, Southern Arizona is known for its desert climate, with very hot summers and mild winters. There are ski resorts in the areas of Flagstaff, Alpine, in addition to the Grand Canyon National Park, there are several national forests, national parks, and national monuments. To the European settlers, their pronunciation sounded like Arissona, the area is still known as alĭ ṣonak in the Oodham language. Another possible origin is the Basque phrase haritz ona, as there were numerous Basque sheepherders in the area, There is a misconception that the states name originated from the Spanish term Árida Zona. See also lists of counties, islands, rivers, lakes, state parks, national parks, Arizona is in the Southwestern United States as one of the Four Corners states. Arizona is the sixth largest state by area, ranked after New Mexico, of the states 113,998 square miles, approximately 15% is privately owned. The remaining area is public forest and park land, state trust land, Arizona is well known for its desert Basin and Range region in the states southern portions, which is rich in a landscape of xerophyte plants such as the cactus. This regions topography was shaped by volcanism, followed by the cooling-off. Its climate has hot summers and mild winters. The state is well known for its pine-covered north-central portion of the high country of the Colorado Plateau. Like other states of the Southwest United States, Arizona has an abundance of mountains, despite the states aridity, 27% of Arizona is forest, a percentage comparable to modern-day France or Germany. The worlds largest stand of pine trees is in Arizona
15.
Boston University
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Boston University is a private research university located in Boston, Massachusetts. The university is nonsectarian, and is affiliated with the United Methodist Church. The university has more than 3,900 faculty members and nearly 33,000 students and it offers bachelors degrees, masters degrees, and doctorates, and medical, dental, business, and law degrees through 17 schools and colleges on two urban campuses. The main campus is situated along the Charles River in Bostons Fenway-Kenmore and Allston neighborhoods, BU is categorized as an R1, Doctoral University in the Carnegie Classification of Institutions of Higher Education. BU is a member of the Boston Consortium for Higher Education, the University was ranked 39th among undergraduate programs at national universities, and 32nd among global universities by U. S. News & World Report in its 2017 rankings. In 1876, BU professor Alexander Graham Bell invented the telephone in a BU lab, American Civil Rights Movement leader and 1964 Nobel Peace Prize winner Dr. Martin Luther King, Jr. received his PhD in Theology from BU in 1955. The Boston University Terriers compete in the NCAAs Division I, BU athletic teams compete in the Patriot League, and Hockey East conferences, and their mascot is Rhett the Boston Terrier. Boston University is well known for hockey, in which it has won five national championships. The University organized formal Centennial observances both in 1939 and 1969, on April 24–25,1839 a group of Methodist ministers and laymen at the Old Bromfield Street Church in Boston elected to establish a Methodist theological school. Set up in Newbury, Vermont, the school was named the Newbury Biblical Institute, in 1847, the Congregational Society in Concord, New Hampshire, invited the Institute to relocate to Concord and offered a disused Congregational church building with a capacity of 1200 people. Other citizens of Concord covered the remodeling costs, one stipulation of the invitation was that the Institute remain in Concord for at least 20 years. The charter issued by New Hampshire designated the school the Methodist General Biblical Institute, with the agreed twenty years coming to a close, the Trustees of the Concord Biblical Institute purchased 30 acres on Aspinwall Hill in Brookline, Massachusetts, as a possible relocation site. The institute moved in 1867 to 23 Pinkney Street in Boston, in 1869, three Trustees of the Boston Theological Institute obtained from the Massachusetts Legislature a charter for a university by name of Boston University. These three were successful Boston businessmen and Methodist laymen, with a history of involvement in educational enterprises and they were Isaac Rich, Lee Claflin, and Jacob Sleeper, for whom Boston Universitys three West Campus dormitories are named. Lee Claflins son, William, was then Governor of Massachusetts, on account of the religious opinions he may entertain, provided, nonetheless, that this section shall not apply to the theological department of said University. Every department of the new university was open to all on an equal footing regardless of sex, race. The Boston Theological Institute was absorbed into Boston University in 1871 as the BU School of Theology, in January 1872 Isaac Rich died, leaving the vast bulk of his estate to a trust that would go to Boston University after ten years of growth while the University was organized. Most of this bequest consisted of real estate throughout the core of the city of Boston and was appraised at more than $1.5 million, Kilgore describes this as the largest single donation to an American college or university to that time
16.
Georgia State University
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Georgia State University is a public research university in downtown Atlanta, Georgia, United States. Founded in 1913, it is one of the University System of Georgias four research universities, Georgia State University offers more than 250 undergraduate and graduate degree programs spread across eight academic colleges with around 3,500 faculty members. It is accredited by the Southern Association of Colleges and Schools, approximately 27% of the student population is considered part-time while 73% of the population is considered full-time. The university is one of only four Georgia universities classified as a Research University/Very High Activity, the university has a full-time faculty count of 1,142, with 69 percent of those faculty members either tenured or on tenure track. GSU has two libraries, University library and Law library, which hold over 4.3 million volumes combined, the university has an economic impact on the Atlanta economy of more than $1.4 billion annually. Initially intended as a school, Georgia State University was established in 1913 as the Georgia School of Technologys Evening School of Commerce. During this time, the school was divided into two divisions, Georgia Evening College, and Atlanta Junior College, in September 1947, the school became affiliated with the University of Georgia and was named the Atlanta Division of the University of Georgia. The school was removed from the University of Georgia in 1955. In 1961, other programs at the school had grown enough that the name was shortened to Georgia State College. It became Georgia State University in 1969, in 1995, the Georgia Board of Regents accorded Georgia State research university status, joining the Georgia Institute of Technology, the University of Georgia, and Augusta University. The first African-American student enrolled at Georgia State in 1962, a year after the integration of the University of Georgia and Georgia Tech. Annette Lucille Hall was a Lithonia social studies teacher who enrolled in the course of the Institute on Americanism and Communism, a course required for all Georgia social studies teachers. The Peachtree Road Race, was started in 1970 by Georgia State cross country coach and dean of men Tim Singleton, the second year, he created the first valuable collectible T-shirt. Over its 100-plus year history, Georgia States growth has required the acquisition and construction of space to suit its needs. In addition, a plaza and walkway system was constructed to connect these buildings with each other over Decatur Street. Georgia States first move into the Fairlie-Poplar district was the acquisition and renovation of the Standard Building, the Haas-Howell Building, and the Rialto Theater in 1996. The Standard and Haas-Howell buildings house classrooms, offices, and practice spaces for the School of Music, and the Rialto is home to GSUs Jazz Studies program and an 833-seat theater. In 1998, the Student Center was expanded toward Gilmer Street and provided a new 400-seat auditorium and space for exhibitions, a new Student Recreation Center opened on the corner of Piedmont Avenue and Gilmer Street in 2001
17.
Warner & Swasey Company
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The Warner & Swasey Company was an American manufacturer of machine tools, instruments, and special machinery. It operated as an independent business firm, based in Cleveland and it was founded as a partnership in 1880 by Worcester Reed Warner and Ambrose Swasey. The company was best known for two types of products, astronomical telescopes and turret lathes. In the decades after World War II, it entered the heavy equipment industry with its acquisition of the Gradall brand. In 1866, Swasey and Warner met as fellow apprentices at the Exeter Machine Works in Exeter, within a few years they went together to Pratt & Whitney in Hartford, Connecticut, which was one of the leading machine tool builders of the era. There they both rose through the ranks, with Warner rising to be in charge of an assembly floor, there Swasey invented the epicycloidal milling machine for cutting true theoretical curves for the milling cutters used for cutting gears. In 1880, Swasey and Warner resigned from Pratt & Whitney in order to start a business together. They investigated Chicago as a place to build their works, but they perceived the Chicago of 1880 as too far west, so they went to Cleveland, Ohio, where their company would stay for the next century. They worked together for 20 years without a corporate agreement, during which time their partnerships principal products were various models of lathes. From the beginning, the partners built both machine tools and telescopes, which reflected their interests in toolmaking, instrument-making, and astronomy, during this early- to mid-20th century, the company was well known in American industry. Its products, both turret lathes and instruments, played prominent roles in the war efforts for both world wars. It was acquired by Bendix Corporation in 1980, the first Warner & Swasey telescope, built in 1881, was sold to Beloit College for its new Smith Observatory and had a 9. 5-inch lens made by Alvan Clark & Sons. Among the notable instruments the company built were the telescopes for Lick Observatory, the United States Naval Observatory, Yerkes Observatory, in 1919, the companys founders donated their private observatory in East Cleveland, Ohio to Case Western Reserve University. Todays Warner and Swasey Observatory grew from that facility, the companys 50th-anniversary book describes the firms giant-telescope-building work as unprofitable overall but a labor of technological love. Its chief competitors in this market segment included Jones & Lamson, Gisholt, military instrument contracts were an important line of work for the company. The U. S. government referred many problems concerning such instruments to the company during the Spanish–American War, instruments produced included range finders of several types, gun-sight telescopes, battery commanders telescopes, telescopic musket sights, and prism binoculars. During World War I, three important kinds of instrument were produced, musket sights, naval gun sights, and panoramic sights, the Gradall became a business of the new owner as the Gradall Division with operations in Cleveland. The Gradall, A Story of American Ingenuity, New Philadelphia, Ohio, USA, JHG Partners, LLC, Warner & Swasey Company, The Warner & Swasey Company, 1880-1920, Cleveland, Ohio, USA, Warner & Swasey Company
18.
Perkins Observatory
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Perkins Observatory is an astronomical observatory in Delaware, Ohio. It is owned and operated by Ohio Wesleyan University, the observatory is named for Hiram Perkins, a professor of mathematics and astronomy at the Ohio Wesleyan University in Delaware, Ohio from 1857 to 1907. A devoutly religious Methodist and a man of convictions, he was also known as an uncompromising and demanding instructor. Perkins graduated from Ohio Wesleyan in 1857, just nine years after the university was founded and he was immediately offered a position on the faculty. Shortly thereafter he married Caroline Barkdull, a graduate from OWU’s Women’s College, in 1861 Perkins temporarily left OWU when the American Civil War began. He intended to enlist in the Union Army, but was deemed unfit for service. Perkins then returned to his hog farm and worked to help feed the troops. Applying his mathematical skills to the science of production, by war’s end he had amassed an impressive fortune. After the war Perkins returned to his university teaching position and lived a frugal life on his small salary. Meanwhile, his business investments caused his fortune to multiply considerably. In 1896 Professor Perkins donated the necessary to build the first of two observatories to bear his name. It is located on West William Street in Delaware, Ohio right next to Hiram and this original “Perkins Astronomical Observatory” later had its name changed to “the Student Observatory” when the second Perkins Observatory was built a quarter century later. Therefore, toward the end of his life Perkins realized he had no living relatives to whom to leave his fortune. Retiring in 1907, Professor Perkins applied himself to the creation of “an astronomical observatory of importance. ”It was his desire that this second observatory be a place where research could be conducted. It took 15 years to find a location and secure the necessary funding. Construction began in 1923 with the frail 90-year-old professor as Guest of Honor at the groundbreaking ceremony, within a year, however, both Hiram and Caroline Perkins had died. Neither saw the completion of the new observatory, the building and telescope mount were completed in less than two years. The work was done by the Warner and Swasey Company of Cleveland, the building included a lecture room, library, office space, walk-in vault, small bedroom for visiting astronomers, and spacious work rooms and metal fabrication shops
19.
Ohio Wesleyan University
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Ohio Wesleyan University is a private liberal arts college in Delaware, Ohio, United States. It was founded in 1842 by Methodist leaders and Central Ohio residents as a nonsectarian institution, Ohio Wesleyan has always admitted students irrespective of religion or race and maintained that the university is forever to be conducted on the most liberal principles. The 200-acre site is 27 miles north of Columbus, Ohio and it includes the main academic and residential campus, the Perkins Observatory, and the Kraus Wilderness Preserve. In 2010, Ohio Wesleyan had the eleventh highest percentage of students among liberal arts colleges for the seventeenth straight year. In its 2015 edition of U. S. college rankings, U. S. News & World Report ranked Ohio Wesleyan 95th among U. S. liberal arts colleges in its 2017 edition. In 1841, Ohio residents Adam Poe and Charles Elliott decided to establish a university of the highest order in central Ohio, to that end, they purchased the Mansion House Hotel, a former health resort with its Sulfur Spring, using funds raised from local residents. Poe and Elliott wrote a charter emphasizing the democratic spirit of teaching, early in the following year they opened the college preparatory Academy and formed a Board of Trustees. Ohio Wesleyans first president, Edward Thomson, stated in his address on August 5,1846 that the school was a product of the liberality of the local people. This liberal philosophy contributed to Ohio Wesleyans vocal opposition to slavery in the 1850s, in the annual celebration for George Washingtons birthday in 1862, second president Frederick Merrick endorsed Ohio Wesleyans ideals of democracy during his oration. During the mid-19th century, Ohio Wesleyan focused on attracting students, adding fields of study, sturges Hall was constructed as the Universitys first library in 1855. In 1873, the added the Department of Natural History housed in Merrick Hall. The Ohio Wesleyan Female College, established in 1853, merged with the university in 1877, between 1876 and 1888, enrollment tripled and music education greatly increased, yet no major buildings were built in this time. By the end of the 19th century, Ohio Wesleyan had added a School of Music, School of Fine Arts, School of Oratory, and Business School to the original College of Liberal Arts. To address the need for new departments and specialized instruction, the administration improved the facilities and courses to make them on par with OWUs new academic position, University Hall, Slocum Library, extensions to the Monnett campus, and athletic facilities were all constructed during that period. Between 1891 and 1895, Ohio Wesleyan specialized the curriculum by establishing departments for physics, zoology, geology, speech, history, French, English, and economics. This specialization encouraged undergraduates to continue studies at level, allowed professional preparation for the Doctor of Philosophy degree. Two professional schools for law and medicine were formed in 1896, in 1905, the Board of Trustees decided to keep Ohio Wesleyan a college, despite the expansion of the curriculum and campus and the word university in the institutions name. The Bachelor of Science degree was abolished, which only the Bachelor of Arts
20.
Delaware, Ohio
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Delaware is a city in and the county seat of Delaware County, Ohio, United States. Delaware was founded in 1808 and was incorporated in 1816 and it is located near the center of Ohio, is about 30 miles north of Columbus, and is part of the Columbus, Ohio Metropolitan Area. The population was 34,753 at the 2010 census, while the Columbus-Marion-Chillicothe, while the city and county of Delaware are named for the Delaware tribe, the city of Delaware itself was founded on a Mingo village called Pluggys Town. The first recorded settler was Joseph Barber in 1807, shortly after other men started settling in the area - Moses Byxbe, William Little, Solomon Smith, and Elder Jacob Drake, Thomas Butler, and Ira Carpenter began building in the area. In 1808, Moses Byxbe built the first framed house on William Street, on March 11,1808, a plan of the city was filed, marking the official founding of the town. Byxbe and the planned the city to be originally on the east bank of the river. However, following the War of 1812, settlers arriving in Delaware in greater numbers. Among some of the earliest settlers were the parents of Rutherford B, Hayes, the 19th President of the United States. The Hayes home no longer stands, but a marker in front of a BP station marks the location. In the early days of the town, a spring was discovered northwest of Joseph Barbers cabin. By 1833, a hotel was built as a spa near the spring. With that effort, Ohio Wesleyan University was founded in 1844, railroads came to the area in April,1851 as Delaware served as a stop on the Cleveland Columbus and Cincinnati Railroad. Additional rail lines were added to serve Delaware providing access to major cities, at the turn of the century, Delaware could boast of its own electric street railway system. In the early 1930s, electric service was provided by the Columbus, Delaware. During the Civil War, Delaware was the home to two Union training camps, the first on the west side of the river for white recruits of the 96th and 121st Ohio Volunteer Infantry were mustered into service. Delaware is located at 40°17′56″N 83°4′19″W, the city is located about 24 miles north of Ohios capital city, Columbus, due north along U. S. Route 23. According to the United States Census Bureau, the city has an area of 19.07 square miles. As of the census of 2010, there were 34,753 people,13,253 households, the population density was 1,833.9 inhabitants per square mile
21.
Thermal expansion
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Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change in temperature. Temperature is a function of the average molecular kinetic energy of a substance. When a substance is heated, the energy of its molecules increases. Thus, the molecules begin vibrating/moving more and usually maintain an average separation. Materials which contract with increasing temperature are unusual, this effect is limited in size, the degree of expansion divided by the change in temperature is called the materials coefficient of thermal expansion and generally varies with temperature. If an equation of state is available, it can be used to predict the values of the expansion at all the required temperatures and pressures. A number of contract on heating within certain temperature ranges. For example, the coefficient of expansion of water drops to zero as it is cooled to 3. Also, fairly pure silicon has a coefficient of thermal expansion for temperatures between about 18 and 120 Kelvin. Unlike gases or liquids, solid materials tend to keep their shape when undergoing thermal expansion, in general, liquids expand slightly more than solids. The thermal expansion of glasses is higher compared to that of crystals, at the glass transition temperature, rearrangements that occur in an amorphous material lead to characteristic discontinuities of coefficient of thermal expansion and specific heat. These discontinuities allow detection of the transition temperature where a supercooled liquid transforms to a glass. Absorption or desorption of water can change the size of common materials. Common plastics exposed to water can, in the long term, the coefficient of thermal expansion describes how the size of an object changes with a change in temperature. Specifically, it measures the change in size per degree change in temperature at a constant pressure. Several types of coefficients have been developed, volumetric, area, which is used depends on the particular application and which dimensions are considered important. For solids, one might only be concerned with the change along a length, the volumetric thermal expansion coefficient is the most basic thermal expansion coefficient, and the most relevant for fluids. In general, substances expand or contract when their temperature changes, substances that expand at the same rate in every direction are called isotropic
22.
U.S. Geological Survey
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The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its resources. The organization has four science disciplines, concerning biology, geography, geology. The USGS is a research organization with no regulatory responsibility. The USGS is a bureau of the United States Department of the Interior, the USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, the current motto of the USGS, in use since August 1997, is science for a changing world. The agencys previous slogan, adopted on the occasion of its anniversary, was Earth Science in the Public Service. Prompted by a report from the National Academy of Sciences, the USGS was created, by a last-minute amendment and it was charged with the classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain. This task was driven by the need to inventory the vast lands added to the United States by the Louisiana Purchase in 1803, the legislation also provided that the Hayden, Powell, and Wheeler surveys be discontinued as of June 30,1879. Clarence King, the first director of USGS, assembled the new organization from disparate regional survey agencies, after a short tenure, King was succeeded in the directors chair by John Wesley Powell. Administratively, it is divided into a Headquarters unit and six Regional Units, Other specific programs include, Earthquake Hazards Program monitors earthquake activity worldwide. The National Earthquake Information Center in Golden, Colorado on the campus of the Colorado School of Mines detects the location, the USGS also runs or supports several regional monitoring networks in the United States under the umbrella of the Advanced National Seismic System. The USGS informs authorities, emergency responders, the media, and it also maintains long-term archives of earthquake data for scientific and engineering research. It also conducts and supports research on long-term seismic hazards, USGS has released the UCERF California earthquake forecast. The USGS National Geomagnetism Program monitors the magnetic field at magnetic observatories and distributes magnetometer data in real time, the USGS operates the streamgaging network for the United States, with over 7400 streamgages. Real-time streamflow data are available online, since 1962, the Astrogeology Research Program has been involved in global, lunar, and planetary exploration and mapping. USGS operates a number of related programs, notably the National Streamflow Information Program. USGS Water data is available from their National Water Information System database
23.
Apollo program
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Five subsequent Apollo missions also landed astronauts on the Moon, the last in December 1972. In these six spaceflights, twelve men walked on the Moon, Apollo ran from 1961 to 1972, with the first manned flight in 1968. It achieved its goal of manned lunar landing, despite the setback of a 1967 Apollo 1 cabin fire that killed the entire crew during a prelaunch test. After the first landing, sufficient flight hardware remained for nine follow-on landings with a plan for extended lunar geological and astrophysical exploration, Budget cuts forced the cancellation of three of these. The crew returned to Earth safely by using the Lunar Module as a lifeboat for these functions, Apollo set several major human spaceflight milestones. It stands alone in sending manned missions beyond low Earth orbit, Apollo 8 was the first manned spacecraft to orbit another celestial body, while the final Apollo 17 mission marked the sixth Moon landing and the ninth manned mission beyond low Earth orbit. The program returned 842 pounds of rocks and soil to Earth, greatly contributing to the understanding of the Moons composition. The program laid the foundation for NASAs subsequent human spaceflight capability, Apollo also spurred advances in many areas of technology incidental to rocketry and manned spaceflight, including avionics, telecommunications, and computers. The Apollo program was conceived during the Eisenhower administration in early 1960, while the Mercury capsule could only support one astronaut on a limited Earth orbital mission, Apollo would carry three astronauts. Possible missions included ferrying crews to a station, circumlunar flights. The program was named after the Greek god of light, music, and the sun by NASA manager Abe Silverstein, who later said that I was naming the spacecraft like Id name my baby. Silverstein chose the name at home one evening, early in 1960, in July 1960, NASA Deputy Administrator Hugh L. Dryden announced the Apollo program to industry representatives at a series of Space Task Group conferences. Preliminary specifications were laid out for a spacecraft with a mission module cabin separate from the module. On August 30, a feasibility study competition was announced, and on October 25, meanwhile, NASA performed its own in-house spacecraft design studies led by Maxime Faget, to serve as a gauge to judge and monitor the three industry designs. In November 1960, John F. Kennedy was elected president after a campaign that promised American superiority over the Soviet Union in the fields of space exploration and missile defense. Beyond military power, Kennedy used aerospace technology as a symbol of prestige, pledging to make the US not first but, first and, first if. Despite Kennedys rhetoric, he did not immediately come to a decision on the status of the Apollo program once he became president and he knew little about the technical details of the space program, and was put off by the massive financial commitment required by a manned Moon landing. On April 12,1961, Soviet cosmonaut Yuri Gagarin became the first person to fly in space, Kennedy was circumspect in his response to the news, refusing to make a commitment on Americas response to the Soviets
24.
United States Naval Observatory Flagstaff Station
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The United States Naval Observatory Flagstaff Station, is an astronomical observatory near Flagstaff, Arizona, USA. It is the national dark-sky observing facility under the United States Naval Observatory, NOFS and USNO combine as the Celestial Reference Frame manager for the U. S. Secretary of Defense. NOFS science supports every aspect of astronomy to some level, providing national support. Work at NOFS covers the gamut of astrometry and astrophysics in order to facilitate its production of accurate/precise astronomical catalogs, multiple observations of each object may themselves take weeks, months or years, by themselves. The United States Naval Observatory, Flagstaff Station celebrated its 50th anniversary of the move there from Washington, dr. John Hall, Director of the Naval Observatorys Equatorial Division from 1947, founded NOFS. Dr. Art Hoag became its first director in 1955, both later were to become directors of nearby Lowell Observatory. NOFS remains active in supporting regional dark skies, both to support its national mission, and to promote and protect a national resource legacy for generations of humans to come. Indeed, despite a history, NOFS has a rich heritage which is derived from its parent organization, USNO. Navy since it saw first light in 1964 and this status will change when the NPOI four 1. 8-meter telescopes see their own first light in the near future. KSAR rides in the arms of a fork mount. The telescope is used in both the spectrum, and in the near infrared, the latter using a sub-30-Kelvin, helium-refrigerated, InSb camera. In 1978, the 1. 55-m telescope was used to discover the moon of dwarf planet Pluto, the Charon discovery led to mass calculations which ultimately revealed how tiny Pluto was, and eventually caused the IAU to reclassify Pluto as a dwarf planet. The 1. 55-meter telescope was used to observe and track NASAs Deep Impact Spacecraft, as it navigated to a successful inter-planetary impact with the celebrated Comet 9p/Tempel. The 61 dome is located on NOFS grounds, with support. The large vacuum coating chamber facility is located in this complex. A dielectric coating capability has also been demonstrated, large optics and telescope components can be moved about NOFS using its suite of cranes, lifts, cargo elevators and specialized carts. The KSAR Telescopes 60-foot diameter steel dome is large for the telescopes aperture. It uses a very wide 2-shutter, vertical slit. 6-meters, by using fast, however, the 61-inch telescope remains unique in its ability to operationally conduct both very high-accuracy relative astrometry to the milliarcsecond level, and close-separation, PSF photometry
25.
United States Naval Research Laboratory
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A few of the laboratorys current specialties include plasma physics, space physics, materials science, and tactical electronic warfare. NRL is one of the first US Government scientific R&D laboratories, having opened in 1923 at the instigation of Thomas Edison, NRLs research expenditures are approximately $1.1 billion per year. The Naval Research Laboratory conducts a variety of basic and scientific research. It has a history of scientific breakthroughs and technological achievements dating back to its foundation in 1923. In many instances the contributions to military technology are declassified decades after those technologies have become widely adopted. In 2011, NRL researchers published 1,398 unclassified scientific & technical articles, book chapters, in 2008, the NRL was ranked #3 among all U. S. institutions holding nanotechnology-related patents, behind IBM and the University of California. The laboratory houses a range of R&D facilities. The most recent additions include the NRL Nanoscience Institutes 5000sqft Class 100 nanofabrication cleanroom and quiet measurement labs, the Naval Research Laboratory has been a crucial piece of the United States space program. Project Vanguard, the first American satellite program, tasked NRL with the design, construction and launch of an artificial satellite, Vanguard I, designed and built at NRL, was the first solar-powered satellite. As of 2013, Vanguard I is still in orbit, making it the longest-lived man-made satellite, Vanguard II was the first satellite to observe the Earths cloud cover and therefore the first meteorological satellite. NRL pioneered the study of the sun Ultraviolet and X-Ray spectrum, along with Project Vanguard, NRL also designed the first satellite tracking system, Minitrack, which became the prototype for future satellite tracking networks. NRLs recently declassified Galactic Radiation and Background I was the first U. S. intelligence satellite, NRLs spacecraft development program continues today with the TacSat-4 experimental tactical reconnaissance & communication satellite. In addition to design, NRL also designs and operates research instruments, such as the Large Angle and Spectrometric Coronagraph Experiment aboard the Solar. NASAs Gamma-ray Large Area Space Telescope was tested at NRL spacecraft testing facilities, NRL scientists have most recently contributed leading research to the study of novas and gamma ray bursts. Modern mechanical fracture mechanics were pioneered at NRL and were applied to solve fracture problems in Navy vessels, commercial aircraft. That knowledge is in use today in applications ranging from design of nuclear reactors to aircraft, submarines. NRLs GaAs inventions were licensed by Rockwell, Westinghouse, Texas Instruments, high-purity GaAs is also used for high-efficiency solar cells like those aboard NASAs Spirit and Opportunity rovers currently on Mars. Fundamental aspects of technology were developed at NRL, including the radar absorption mechanisms in ferrite-containing materials
26.
Lowell Observatory Near-Earth-Object Search
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Lowell Observatory Near-Earth-Object Search was a project designed to discover asteroids and comets that orbit near the Earth. The project, funded by NASA, was directed by Dr. Ted Bowell of Lowell Observatory in Flagstaff, the LONEOS project began in 1993 and ran until the end of February 2008. LONEOS, in its configuration, used a 0. 6-meter f/1.8 Schmidt telescope, acquired from Ohio Wesleyan University in 1990. This combination of instruments provided a field of view of 2.88 by 2.88 degrees and it had a maximum nightly scan area of about 1,000 square degrees. The instrument could cover the entire accessible dark sky in about a month, the CCD has detected asteroids as faint as visual magnitude 19.8 but its typical limiting visual magnitude was 19.3. The instrument is located at Lowell Observatorys dark sky site, Anderson Mesa Station, near Flagstaff, Arizona, two were used for frame reductions, one for telescope pointing control and one for camera control. The camera control software had scripting capability and could control all the other computers, asteroids were found by obtaining four pictures of the same region of sky, each frame temporally separated by 15 to 30 minutes. The set of four frames were then submitted to reduction software which located all star-like sources on the frame, the observer visually examined all asteroid detections that had motion different from a typical main-belt asteroid. Human examination was required because most putative NEO detections were not real, all asteroid positions were converted to equatorial coordinates. Various USNO star catalogs were used for this conversion until 2007, then the Sloan Digital Sky Survey catalog was used, along with supplemental information from the Carlsberg Catalog and the 2MASS catalog. Asteroid brightness was converted to standard visual magnitude and these data, along with the time of the observations, were sent to the Minor Planet Center from which they were distributed to the scientific community. Potential near-Earth objects were handled expeditiously so that other observers could locate the asteroid on the same night, telescope operation was automated to the extent that the survey could be run all night without observer intervention. However, the telescope was operated in the automatic mode because an observer was required to reduce data promptly. During the period of LONEOS operation, several other NASA funded NEO searches were underway and these projects include LINEAR, CSS, Spacewatch, and NEAT. Amateur observers made a significant contribution during this time with independent NEO discoveries, the table below lists the number of discoveries made by LONEOS each year of operation. Asteroids thought to be larger than one kilometer in diameter were used as benchmarks in assessing survey completeness, hence, some table elements have two numbers separated by a slash. The second number represents the number of larger than one kilometer. The column labeled Asteroid Observations is the number of sent to the MPC
27.
Schmidt camera
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A Schmidt camera, also referred to as the Schmidt telescope, is a catadioptric astrophotographic telescope designed to provide wide fields of view with limited aberrations. The design was invented by Bernhard Schmidt in 1930, a recent example is the Kepler spacecraft exoplanet finder. Other related designs are the Wright Camera and Lurie–Houghton telescope, the Schmidt camera was invented by German-Estonian optician Bernhard Schmidt in 1930. Its optical components are an easy-to-make spherical primary mirror, and an aspherical correcting lens, known as a Schmidt corrector plate, the film or other detector is placed inside the camera, at the prime focus. The design is noted for allowing very fast focal ratios, while controlling coma, Schmidt cameras have very strongly curved focal planes, thus requiring that the film, plate, or other detector be correspondingly curved. A field flattener, in its simplest form a lens in front of the film plate or detector, is sometimes used. Since the corrector plate is at the center of curvature of the mirror in this design the tube length can be very long for a wide-field telescope. Because of its field of view, the Schmidt camera is typically used as a survey instrument. These include astronomical surveys, comet and asteroid searches, and nova patrols, in addition, Schmidt cameras and derivative designs are frequently used for tracking artificial earth satellites. The first relatively large Schmidt telescopes were built at Hamburg Observatory, between 1945 and 1980, about 8 more large Schmidt telescopes were built around the world. One particularly famous and productive Schmidt camera is the Oschin Schmidt Telescope at Palomar Observatory and this instrument was used in the National Geographic Society - Palomar Observatory Sky Survey, the POSS-II survey, the Palomar-Leiden Surveys, and other projects. The technical improvements developed during this survey encouraged the development of the Second Palomar Observatory Sky Survey, the telescope used in the Lowell Observatory Near-Earth-Object Search is also a Schmidt camera. The Schmidt telescope of the Karl Schwarzschild Observatory is the largest Schmidt camera of the world, a Schmidt telescope was at the heart of the Hipparcos satellite from the European Space Agency. This was used in the Hipparcos Survey which mapped the distances of more than a million stars with unprecedented accuracy - this included 99% of all stars up to magnitude 11. The spherical mirror used in this telescope was extremely accurate, if scaled up to the size of the Atlantic Ocean, the Kepler photometer, mounted on the Kepler probe, and orbiting since March 2009, is the largest Schmidt camera launched into space. Starting in the early 1970s, Celestron marketed an 8-inch Schmidt Camera, the camera was focused in the factory and was made of materials with low expansion coefficients so it would never need to be focused in the field. Early models required the photographer to cut and develop individual frames of 35 mm film as the holder could only hold one frame of film. About 300 Celestron Schmidt Cameras were produced, the Schmidt system was popular, used in reverse, for television projection systems
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Asteroid
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Asteroids are minor planets, especially those of the inner Solar System. The larger ones have also been called planetoids and these terms have historically been applied to any astronomical object orbiting the Sun that did not show the disc of a planet and was not observed to have the characteristics of an active comet. As minor planets in the outer Solar System were discovered and found to have volatile-based surfaces that resemble those of comets, in this article, the term asteroid refers to the minor planets of the inner Solar System including those co-orbital with Jupiter. There are millions of asteroids, many thought to be the remnants of planetesimals. The large majority of known asteroids orbit in the belt between the orbits of Mars and Jupiter, or are co-orbital with Jupiter. However, other orbital families exist with significant populations, including the near-Earth objects, individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups, C-type, M-type, and S-type. These were named after and are identified with carbon-rich, metallic. The size of asteroids varies greatly, some reaching as much as 1000 km across, asteroids are differentiated from comets and meteoroids. In the case of comets, the difference is one of composition, while asteroids are composed of mineral and rock, comets are composed of dust. In addition, asteroids formed closer to the sun, preventing the development of the aforementioned cometary ice, the difference between asteroids and meteoroids is mainly one of size, meteoroids have a diameter of less than one meter, whereas asteroids have a diameter of greater than one meter. Finally, meteoroids can be composed of either cometary or asteroidal materials, only one asteroid,4 Vesta, which has a relatively reflective surface, is normally visible to the naked eye, and this only in very dark skies when it is favorably positioned. Rarely, small asteroids passing close to Earth may be visible to the eye for a short time. As of March 2016, the Minor Planet Center had data on more than 1.3 million objects in the inner and outer Solar System, the United Nations declared June 30 as International Asteroid Day to educate the public about asteroids. The date of International Asteroid Day commemorates the anniversary of the Tunguska asteroid impact over Siberia, the first asteroid to be discovered, Ceres, was found in 1801 by Giuseppe Piazzi, and was originally considered to be a new planet. In the early half of the nineteenth century, the terms asteroid. Asteroid discovery methods have improved over the past two centuries. This task required that hand-drawn sky charts be prepared for all stars in the band down to an agreed-upon limit of faintness. On subsequent nights, the sky would be charted again and any moving object would, hopefully, the expected motion of the missing planet was about 30 seconds of arc per hour, readily discernible by observers
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Near-Earth object
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A near-Earth object is any small Solar System body whose orbit brings it into proximity with Earth. By definition, a solar system body is a NEO if its closest approach to the Sun is less than 1.3 astronomical unit and it is now widely accepted that collisions in the past have had a significant role in shaping the geological and biological history of the Earth. NEOs have become of increased interest since the 1980s because of increased awareness of the potential danger some of the asteroids or comets pose, and mitigations are being researched. In January 2016, NASA announced the Planetary Defense Coordination Office to track NEOs larger than 30 to 50 meters in diameter and coordinate an effective threat response, NEAs have orbits that lie partly between 0.983 and 1.3 AU away from the Sun. When a NEA is detected it is submitted to the IAUs Minor Planet Center for cataloging, some NEAs orbits intersect that of Earths so they pose a collision danger. The United States, European Union, and other nations are currently scanning for NEOs in an effort called Spaceguard. In the United States and since 1998, NASA has a mandate to catalogue all NEOs that are at least 1 kilometer wide. In 2006, it was estimated that 20% of the objects had not yet been found. In 2011, largely as a result of NEOWISE, it was estimated that 93% of the NEAs larger than 1 km had been found, as of 5 February 2017, there have been 875 NEAs larger than 1 km discovered, of which 157 are potentially hazardous. The inventory is much less complete for smaller objects, which still have potential for scale, though not global. Potentially hazardous objects are defined based on parameters that measure the objects potential to make threatening close approaches to the Earth. Mostly objects with an Earth minimum orbit intersection distance of 0.05 AU or less, objects that cannot approach closer to the Earth than 0.05 AU, or are smaller than about 150 m in diameter, are not considered PHOs. This makes them a target for exploration. As of 2016, three near-Earth objects have been visited by spacecraft, more recently, a typical frame of reference for looking at NEOs has been through the scientific concept of risk. In this frame, the risk that any near-Earth object poses is typically seen through a lens that is a function of both the culture and the technology of human society, NEOs have been understood differently throughout history. Each time an NEO is observed, a different risk was posed and it is not just a matter of scientific knowledge. Such perception of risk is thus a product of religious belief, philosophic principles, scientific understanding, technological capabilities, and even economical resourcefulness.03 E −0.4 megatonnes. For instance, it gives the rate for bolides of 10 megatonnes or more as 1 per thousand years, however, the authors give a rather large uncertainty, due in part to uncertainties in determining the energies of the atmospheric impacts that they used in their determination
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Astrograph
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An astrograph is a telescope designed for the sole purpose of astrophotography. Astrographs are usually used in wide field surveys of the sky as well as detection of objects such as asteroids, meteors. Most research telescopes in this class are refractors, although there are many reflecting designs such as the Ritchey-Chrétien, the main parameters of an Astrograph are the diameter and f-ratio of the objective, which determine the field of view and image scale on the photographic plate or CCD detector. The objective of an astrograph is usually not very large, on the order of 20 to 50 cm, the shape of the focal plane is often designed to work in conjunction with a specific shaped photographic plate or CCD detector. The objective is designed to produce a large, flat. They may even be designed to certain wavelengths of light to match the type of film they are designed to use. Wide-angle astrographs with short f-ratios are used for photographing a huge area of sky, astrographs with higher f-ratios are used in more precise measurements. Many observatories of the world are equipped with the so-called normal astrographs with an aperture of around 13 inches, the purpose of a normal astrograph is to create images where the scale of the image at the focal plane is a standard of approximately 60 arcsecs/mm. Astrographs used in astrometry record images that are used to map the positions of objects over a large area of the sky. These maps are published in catalogs to be used in further study or to serve as reference points for deep-space imaging. Astrographs used for stellar classification sometimes consist of two telescopes on the same mount. Each sky field can be photographed in two colors. Each telescope may have individually designed non-achromatic objectives to focus the desired wavelength of light which is paired with the respective color-sensitive photographic plate. In other cases a single telescope is used to make two exposures of the part of the sky with different filters and color sensitive film used on each exposure. Two-color photography lets astronomers measure the color, as well as the brightness, knowing the color type and magnitudes lets astronomers determine the distance of a star. Sky fields that are photographed twice, decades apart in time, by taking two exposures of the same section of the sky days or weeks apart, it is possible to find objects such as asteroids, meteors, comets, variable stars, novae, and even unknown planets. Sometimes objects can even be found in one exposure since a fast moving object appear as a line in a long exposure. One well-known case of a used in a discovery is Clyde Tombaugh’s discovery of the dwarf planet Pluto in 1930
31.
Alvan Clark & Sons
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Alvan Clark & Sons was an American maker of optics that became famous for crafting lenses for some of the largest refracting telescopes of the 19th and early 20th centuries. Founded in 1846 in Cambridgeport, Massachusetts, by Alvan Clark, five times, the firm built the largest refracting telescopes in the world. The Clark firm gained worldwide fame and distribution, wrote one author on astronomy in 1899, the 18. 5-inch Dearborn telescope was commissioned in 1856 by the University of Mississippi. The outbreak of war prevented them from ever taking ownership. As a result, it was being tested in Cambridgeport when Alvan Graham observed Sirius B in 1862, in 1873 they built the 26-inch objective lens for the refractor at the United States Naval Observatory. The company also built a number of instruments, which are still highly prized among collectors. The companys assets were acquired by the Sprague-Hathaway Manufacturing Company in 1933, most of Clarks equipment was disposed of as scrap during World War II, and Sprague-Hathaway itself was liquidated in 1958. Alvan Clark & Sons Telescopes Chabot Space & Science Center, Oakland, California Charles Sumner Tainter Deborah Jean Warner, ariail, Alvan Clark & Sons, artists in optics Richmond, VA. Willmann-Bell, in association with National Museum of American History, Smithsonian Institution,1995,298 p. ISBN 0-943396-46-8 Timothy Ferris, Seeing in the Dark Simon & Schuster 2002, 117p
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Clyde Tombaugh
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Clyde William Tombaugh was an American astronomer. He discovered Pluto in 1930, the first object to be discovered in what would later be identified as the Kuiper belt, at the time of discovery, Pluto was considered a planet but was later reclassified as a dwarf planet in 2006. He also called for the scientific research of unidentified flying objects. Tombaugh was born in Streator, Illinois, son of Muron Dealvo Tombaugh, a farmer, after his family moved to Burdett, Kansas in 1922, Tombaughs plans for attending college were frustrated when a hailstorm ruined his familys farm crops. Starting in 1926, he built several telescopes with lenses and mirrors by himself, to better test his telescope mirrors, Tombaugh, with just a pick and shovel, dug a pit 24 feet long,8 feet deep, and 7 feet wide. This provided a constant air temperature, free of air currents and he sent drawings of Jupiter and Mars to the Lowell Observatory, which offered him a job. Tombaugh worked there from 1929 to 1945, following his discovery of Pluto, Tombaugh earned bachelors and masters degrees in astronomy from the University of Kansas in 1936 and 1938. During World War II he taught naval personnel navigation at Northern Arizona University and he worked at White Sands Missile Range in the early 1950s, and taught astronomy at New Mexico State University from 1955 until his retirement in 1973. The asteroid 1604 Tombaugh, discovered in 1931, is named after him and he discovered hundreds of asteroids, beginning with 2839 Annette in 1929, mostly as a by-product of his search for Pluto and his searches for other celestial objects. Tombaugh named some of them after his wife, children and grandchildren, the Royal Astronomical Society awarded him the Jackson-Gwilt Medal in 1931. In 1980, he wrote a book Out of the Darkness, in August 1992, JPL scientist Robert Staehle called Tombaugh, requesting permission to visit his planet. I told him he was welcome to it, Tombaugh later remembered, though hes got to go one long, the call eventually led to the launch of the New Horizons space probe to Pluto in 2006. Following the passage on July 14,2015 of Pluto by the New Horizons spacecraft the Cold Heart of Pluto was named Tombaugh Regio, Tombaugh died on January 17,1997, when he was in Las Cruces, New Mexico, at the age of 90. A small portion of his ashes was placed aboard the New Horizons spacecraft, the container includes the inscription, Interred herein are remains of American Clyde W. Tombaugh, discoverer of Pluto and the solar systems third zone. Adelle and Murons boy, Patricias husband, Annette and Aldens father, astronomer, teacher, punster, Tombaugh was survived by his wife, Patricia, and their children, Annette and Alden. Tombaugh was an active Unitarian-Universalist, and he and his wife helped found the Unitarian Universalist Church of Las Cruces, through the daughter of his youngest brother, Robert M. Tombaugh is the great uncle of Los Angeles Dodgers pitcher Clayton Kershaw. Tombaugh used the observatorys 13-inch astrograph to take photographs of the section of sky several nights apart. He then used a blink comparator to compare the different images, when he shifted between the two images, a moving object, such as a planet, would appear to jump from one position to another, while the more distant objects such as stars would appear stationary
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Pluto
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Pluto is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune. It was the first Kuiper belt object to be discovered, Pluto was discovered by Clyde Tombaugh in 1930 and was originally considered to be the ninth planet from the Sun. After 1992, its planethood was questioned following the discovery of objects of similar size in the Kuiper belt. In 2005, Eris, which is 27% more massive than Pluto, was discovered and this led the International Astronomical Union to define the term planet formally in 2006, during their 26th General Assembly. That definition excluded Pluto and reclassified it as a dwarf planet, Pluto is the largest and second-most-massive known dwarf planet in the Solar System and the ninth-largest and tenth-most-massive known object directly orbiting the Sun. It is the largest known trans-Neptunian object by volume but is less massive than Eris, like other Kuiper belt objects, Pluto is primarily made of ice and rock and is relatively small—about one-sixth the mass of the Moon and one-third its volume. It has an eccentric and inclined orbit during which it ranges from 30 to 49 astronomical units or AU from the Sun. This means that Pluto periodically comes closer to the Sun than Neptune, light from the Sun takes about 5.5 hours to reach Pluto at its average distance. Pluto has five moons, Charon, Styx, Nix, Kerberos. Pluto and Charon are sometimes considered a system because the barycenter of their orbits does not lie within either body. The IAU has not formalized a definition for binary dwarf planets, on July 14,2015, the New Horizons spacecraft became the first spacecraft to fly by Pluto. During its brief flyby, New Horizons made detailed measurements and observations of Pluto, on October 25,2016, at 05,48 pm ET, the last bit of data was received from New Horizons from its close encounter with Pluto on July 14,2015. In the 1840s, Urbain Le Verrier used Newtonian mechanics to predict the position of the then-undiscovered planet Neptune after analysing perturbations in the orbit of Uranus. Subsequent observations of Neptune in the late 19th century led astronomers to speculate that Uranuss orbit was being disturbed by another planet besides Neptune, by 1909, Lowell and William H. Pickering had suggested several possible celestial coordinates for such a planet. Lowell and his observatory conducted his search until his death in 1916, unknown to Lowell, his surveys had captured two faint images of Pluto on March 19 and April 7,1915, but they were not recognized for what they were. There are fourteen other known prediscovery observations, with the oldest made by the Yerkes Observatory on August 20,1909. Percivals widow, Constance Lowell, entered into a legal battle with the Lowell Observatory over her late husbands legacy. Tombaughs task was to image the night sky in pairs of photographs, then examine each pair
