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Takahashi Seisakusho
is a Japanese manufacturer of telescopes and related equipment (such as eyepieces and equatorial mounts) founded in 1932 by Kitaro Takahashi in Tokyo. Originally started as a foundry, Takahashi began manufacturing optical equipment after WWII in 1946. Often known simply as 'Tak', the brand is especially noted amongst amateur astronomers for its range of apochromatic refractors, but also produces various types of reflectors, and instruments featuring compound optics. All Takahashi telescopes and mounts are made in Japan using traditional manufacturing methods, such as sand casting, with nearly all parts made in-house. Takahashi pioneered the use of fluorite crystal in place of one of the glass elements in the objective lens of an astronomical telescope, although this material had previously been used in other optical devices. The company's name would become synonymous with the use of this type of crystal. In recent years however, Takahashi has produced some telescopes using e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embry-Riddle Observatory
The Embry–Riddle Observatory is an astronomical observatory owned and operated by Embry-Riddle Aeronautical University, Daytona Beach. Hosting an array of optical instruments, this observatory is situated on the roof of the College of Arts and Sciences building in Daytona Beach, Florida. History Embry-Riddle Observatory, originally known as Embry-Riddle Creekside Observatory, began in a Technical Innovations Pro-Dome dome located between the Lehman Engineering Building and a creek that ran through campus. In 2012, Embry-Riddle broke ground on the new 140,000 sq-ft College of Arts and Sciences building which included a Ash Dome on the roof. Upon completion of the building, existing telescopes were moved from the Creekside Observatory to the new building and the university installed a new 1-meter Ritchey–Chrétien telescope in June, 2014. General information The fifth floor of the College of Arts and Sciences building is used exclusively for astronomy and astronomical res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mirasteilas Observatory
The Mirasteilas Observatory (german: Sternwarte Mirasteilas; Romansh for "stargazer") is an astronomical observatory in Falera in the canton of Grisons in Switzerland. With its 90-centimeter telescope it is the largest publicly accessible observatory in Switzerland. History In 2001, the Portuguese-born local community member José De Queiroz, innkeeper in Falera and a member of the Astronomical Society of the Grisons (Graubünden), organized the first astronomy meeting in Falera. Owing to its easy accessibility, its elevated position on a terrace with a broad sky to the west, south, and east and low light pollution, the place offers ideal conditions for observing celestial bodies. During the next telescope meeting in Falera in 2002 the question was raised whether an observatory could be created here. The municipal council recognized that the construction of an observatory could be a big gain for the village, since no similar investment had been made in the Grisons by that time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equatorial Mount
An equatorial mount is a mount for instruments that compensates for Earth's rotation by having one rotational axis, the polar axis, parallel to the Earth's axis of rotation. This type of mount is used for astronomical telescopes and cameras. The advantage of an equatorial mount lies in its ability to allow the instrument attached to it to stay fixed on any celestial object with diurnal motion by driving one axis at a constant speed. Such an arrangement is called a sidereal or clock drive. Equatorial mounts achieve this by aligning their rotational axis with the Earth, a process known as polar alignment. Astronomical telescope mounts In astronomical telescope mounts, the equatorial axis (the '' right ascension'') is paired with a second perpendicular axis of motion (known as the '' declination''). The equatorial axis of the mount is often equipped with a motorized "''clock drive''", that rotates that axis one revolution every 23 hours and 56 minutes in exact sync with the appar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tokyo
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 million residents ; the city proper has a population of 13.99 million people. Located at the head of Tokyo Bay, the prefecture forms part of the Kantō region on the central coast of Honshu, Japan's largest island. Tokyo serves as Japan's economic center and is the seat of both the Japanese government and the Emperor of Japan. Originally a fishing village named Edo, the city became politically prominent in 1603, when it became the seat of the Tokugawa shogunate. By the mid-18th century, Edo was one of the most populous cities in the world with a population of over one million people. Following the Meiji Restoration of 1868, the imperial capital in Kyoto was moved to Edo, which was renamed "Tokyo" (). Tokyo was devastate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apochromatic
An apochromat, or apochromatic lens (apo), is a photographic or other lens that has better correction of chromatic and spherical aberration than the much more common achromat lenses. Explanation Chromatic aberration is the phenomenon of different colors focusing at different distances from a lens. In photography, chromatic aberration produces soft overall images, and color fringing at high-contrast edges, like an edge between black and white. Astronomers face similar problems, particularly with telescopes that use lenses rather than mirrors. ''Achromatic'' lenses are corrected to bring ''two'' wavelengths into focus in the same plane – typically red (~0.590 µm) and blue (~0.495 µm). ''Apo''chromatic lenses are designed to bring ''three'' colors into focus in the same plane – typically red (~0.620 µm), green (~0.530 µm), and blue (~0.465 µm). The residual color error (secondary spectrum) can be up to an order of magnitude less than for an achro ... [...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 (optics), lens as its objective (optics), objective to form an image (also referred to a dioptrics, dioptric telescope). The refracting telescope design was originally used in spyglasses and astronomy, astronomical telescopes but is also used for long-focus lens, 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 optical train, 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, tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflecting 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 catoptrics, 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 eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand Casting
Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. Over 60% of all metal castings are produced via sand casting process. Molds made of sand are relatively cheap, and sufficiently refractory even for steel foundry use. In addition to the sand, a suitable bonding agent (usually clay) is mixed or occurs with the sand. The mixture is moistened, typically with water, but sometimes with other substances, to develop the strength and plasticity of the clay and to make the aggregate suitable for molding. The sand is typically contained in a system of frames or mold boxes known as a flask. The mold cavities and gate system are created by compacting the sand around models called patterns, by carving directly into the sand, or by 3D printing. Basic pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorite
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite. Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Dispersion Glass
Low-dispersion glass (LD glass) is a type of glass with a reduction in chromatic aberration (less rainbow effect). Crown glass is an example of a relatively inexpensive low-dispersion glass. ''Special low dispersion glass'' (SLD glass) and ''extraordinary low-dispersion glass'' (ELD glass) are glasses with yet lower dispersion (and yet higher price). Other glasses in this class are ''extra-low-dispersion glass'' (ED glass), and ''ultra-low-dispersion glass'' (UL glass). Application Low-dispersion glasses are particularly used to reduce chromatic aberration, most often used in achromatic doublets. The positive element is made of a low-dispersion glass, the negative element from a high-dispersion glass. To counteract the effect of the negative lens, the positive lens has to be thicker. Achromatic doublets therefore have higher thickness and weight than the equivalent non-chromatic-corrected single lenses. In comparison to telephoto lenses, shorter focal length objectives benefit les ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Objective Lens
In optical engineering, the objective is the optical element that gathers light from the object being observed and Focus (optics), focuses the ray (optics), light rays to produce a real image. Objectives can be a single Lens (optics), lens or mirror, or combinations of several optical elements. They are used in microscopes, binoculars, telescopes, cameras, slide projectors, CD players and many other optical instruments. Objectives are also called object lenses, object glasses, or objective glasses. Microscope objectives The objective lens of a microscope is the one at the bottom near the sample. At its simplest, it is a very high-powered magnifying glass, with very short focal length. This is brought very close to the specimen being examined so that the light from the specimen comes to a focus inside the microscope tube. The objective itself is usually a cylinder containing one or more lenses that are typically made of glass; its function is to collect light from the sample. Magn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoober Observatory
J A Jones Hoober Observatory is a privately owned observatory located in South Yorkshire, England near to the villages of Hoober and Wentworth, South Yorkshire, Wentworth, North-northwest of Rotherham. It can be found about east of Hoober Stand. The observatory is owned and operated by Mexborough & Swinton Astronomical Society (NPO). Architecture and design The observatory consists of a square building topped by a 5-metre diameter dome. The observatory was built by the members between 1991 and 1993. Originally the dome was only in diameter. In 1999 a major refurbishment of the observatory was completed including a new 5-metre diameter dome, which was designed & built by the members over the preceding 3–4 years. A project is currently underway (2018) to extend the observatory by adding a 5-metre square extension (public room). The building is also undergoing extensive refurbishment inside and outside to create a toilet and improve facilities for disabled visitors. It is p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
