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James Lick Telescope
The James Lick Telescope is a refracting telescope built in 1888. It has a lens in diameter—a major achievement in its day. The instrument remains in operation and public viewing is allowed on a limited basis. Also called the "Great Lick Refractor" or simply "Lick Refractor", it was the largest refracting telescope in the world until 1897 and now ranks third, after the 40-inch refractor at the Yerkes Observatory and the Swedish 1-m Solar Telescope. The telescope is located at the University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Fran ...'s Lick Observatory atop Mount Hamilton at an elevation of above sea level. The instrument is housed inside a dome that is powered by hydraulic systems that raise and lower the floor, rotate the dome and drive the clock mech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lick Telescope 1889
Lick may refer to: * Licking, the action of passing the tongue over a surface Places * Lick (crater), a crater on the Moon named after James Lick * 1951 Lick, an asteroid named after James Lick * Lick Township, Jackson County, Ohio, United States People * Lick (surname), people with "Lick" as a surname ** Dennis Lick (born 1954), American professional football lineman ** James Lick (1796–1876), American carpenter, land baron, and patron of the sciences * J. C. R. Licklider (1915–1990), American computer scientist, nicknamed "Lick" Music * ''Lick'' (album), by The Lemonheads * Lick (band), an American band, fl. 1990s * Lick (music), a short phrase, or series of notes, often improvised by a musician ** The Lick, a jazz lick, commonly known as 'The Lick' * "Lick" (Joi song), 2002 * "Lick" (Shenseea and Megan Thee Stallion song), 2022 Nature * Lick (stream), a small or ephemeral stream * Salt lick, a salt deposit that animals regularly lick Other uses * Lick's Homeburgers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Largest Optical Telescopes In The 19th Century
List of largest optical telescopes in the 19th century, are listings of what were, for the time period of the 19th century large optical telescopes. See List of largest optical telescopes in the 20th century for the 1900s. The list includes various refractor and reflector that were active some time between about 1799 to 1901. The main reflecting technology early on, speculum metal reflected some 2/3 of light, and also had higher maintenance due to tarnishing. Another technology were the 2-element refractors, which were extensively used in 19th century observatories despite their small apertures compared to the largest metal mirror, and later glass telescopes. The technology for silver-coated glass mirrors was developed in the mid-19th century, but was slow to catch on. A major technology advance of this time was the development of astrophotography, and some telescopes were tailored to this application. Also, a wide variety of scientific instruments were developed, such as for spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver On Glass
Silvering is the chemical process of coating a non-conductive substrate such as glass with a reflective substance, to produce a mirror. While the metal is often silver, the term is used for the application of any reflective metal. Process Most common household mirrors are "back-silvered" or "second-surface", meaning that the light reaches the reflective layer after passing through the glass. A protective layer of paint is usually applied to protect the back side of the reflective surface . This arrangement protects the fragile reflective layer from corrosion, scratches, and other damage. However, the glass layer may absorb some of the light and cause distortions and optical aberrations due to refraction at the front surface, and multiple additional reflections on it, giving rise to "ghost images" (although some optical mirrors such as Mangins, take advantage of it). Therefore, precision optical mirrors normally are "front-silvered" or " first-surface", meaning that the re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossley Telescope
The Crossley telescope is a reflecting telescope located at Lick Observatory in the U.S. state of California. It was used between 1895 to 2010, and was donated to the observatory by Edward Crossley, its namesake. It was the largest glass reflecting telescope in the United States for several years after its recommissioning in California. Lick Director, James Edward Keeler, remarked of the Crossley in 1900, "... by far the most effective instrument in the Observatory for certain class of astronomical work." History Given to the Lick Observatory in 1895 by British politician Edward Crossley, it was rebuilt from the ground up as it was on a very flimsy mounting. It was last used in 2010 in the search for extra-solar planets but has been taken out of service due to budget cuts. The mirror, and some of the initial mounts, came from the 36-inch reflector originally mounted in Andrew Ainslie Common's backyard Ealing observatory. He had used it from 1879 to 1886 to prove the concep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Williams Bay, Wisconsin
Williams Bay is a village in Walworth County, Wisconsin, United States. It is one of three municipalities on Geneva Lake. The population was 2,564 at the 2010 census. History The village was named for Captain Israel Williams of Massachusetts, who, with several of his sons, settled in the area in 1837. Much of the surrounding area was settled in the early 19th century by surveyors plotting roadways from the East. Williams Bay became a vacation spot for wealthy Chicagoans displaced by the Great Chicago Fire of 1871. The village continues to attract vacationers from Chicago, Milwaukee and elsewhere. In 1873, mail jumping was established on Geneva Lake as a means to provide postal service to lakeside homes. The tradition continues today. Each year between June 15 and September 15, jumpers deliver mail to piers along the lake on behalf of the US Postal Service. In 1886, a training camp was established by leaders of the YMCA at Williams Bay. The camp’s programs later evolved i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, 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 first known practical telescopes were refracting telescopes with glass lenses and were invented in the Netherlands at the beginning of the 17th century. They were used for both terrestrial applications and astronomy. The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. Etymology The word ''telescope'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An optical system typically has many openings or structures that limit the ray bundles (ray bundles are also known as ''pencils'' of light). These structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that primarily determines the ray cone angle and brightness at the image point. In some contexts, especially in photography and astronomy, ''aperture'' refers to the diameter of the aperture stop rather than the physical stop or the opening itself. For example, in a telescope, the apertur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractor
A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope). The refracting telescope design was originally used in spyglasses and astronomical telescopes but is also used for long-focus camera lenses. Although large refracting telescopes were very popular in the second half of the 19th century, for most research purposes, the refracting telescope has been superseded by the reflecting telescope, which allows larger apertures. A refractor's magnification is calculated by dividing the focal length of the objective lens by that of the eyepiece. Refracting telescopes typically have a lens at the front, then a long tube, then an eyepiece or instrumentation at the rear, where the telescope view comes to focus. Originally, telescopes had an objective of one element, but a century later, two and even three element lenses were made. Refracting telescope is a technology t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflector Telescope
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic aberration. Although reflecting telescopes produce other types of optical aberrations, it is a design that allows for very large diameter objectives. Almost all of the major telescopes used in astronomy research are reflectors. Many variant forms are in use and some 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 sometimes referred to as a catoptric telescope. From the time of Newton to the 1800s, the mirror itself was made of metal usually speculum metal. This type included Newton's first designs and even the largest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldebaran
Aldebaran (Arabic: “The Follower”, "الدبران") is the brightest star in the zodiac constellation of Taurus. It has the Bayer designation α Tauri, which is Latinized to Alpha Tauri and abbreviated Alpha Tau or α Tau. Aldebaran varies in brightness from an apparent visual magnitude 0.75 down to 0.95, making it (typically) the fourteenth-brightest star in the night sky. It is located at a distance of approximately 65 light-years from the Sun. The star lies along the line of sight to the nearby Hyades cluster. Aldebaran is a giant star that is cooler than the Sun with a surface temperature of , but its radius is about 44 times the Sun's, so it is over 400 times as luminous. It spins slowly and takes 520 days to complete a rotation. Aldebaran is believed to host a planet several times the mass of Jupiter, named . The planetary exploration probe Pioneer 10 is heading in the general direction of the star and should make its closest approach in about two millio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hacksaw
A hacksaw is a fine-toothed saw, originally and mainly made for cutting metal. The equivalent saw for cutting wood is usually called a bow saw. Most hacksaws are hand saws with a C-shaped walking frame that holds a blade under tension. Such hacksaws have a handle, usually a pistol grip, with pins for attaching a narrow disposable blade. The frames may also be adjustable to accommodate blades of different sizes. A screw or other mechanism is used to put the thin blade under tension. On hacksaws, as with most frame saws, the blade can be mounted with the teeth facing toward or away from the handle, resulting in cutting action on either the push or pull stroke. In normal use, cutting vertically downwards with work held in a bench vise, hacksaw blades are set to be facing forwards. History While saws for cutting metal had been in use for many years, significant improvements in longevity and efficiency were made in the 1880s by Max Flower-Nash. George N. Clemson, a founde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
