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49-484: The notable feature of the HPT – and the reason for its name – was the design of its mount . Instead of the typical mounting where the telescope moves on two rotating axes, the mirror cell was supported by six extensible (variable-length) struts, an arrangement known as a Stewart platform . This configuration allowed the telescope to move in all six spatial degrees of freedom and provided strong structural integrity. Furthermore,

98-567: A blind spot near the zenith, and for objects near the celestial equator the field rotation is minimized. It has the disadvantage of having all the mass, complexity, and engineering problems of its equatorial counterpart, so is only used in specialty applications such as satellite tracking. These mounts may include a third azimuth axis (an altitude-altitude-azimuth mount ) to rotate the entire mount into an orientation that allows smoother tracking. The equatorial mount has north-south "polar axis" tilted to be parallel to Earth's polar axis that allows

147-425: A celestial object in a telescope equipped with a DSC computer, one does not need to look up the specific RA and Dec coordinates in a book or other resource, and then adjust the telescope to those numerical readings. Rather, the object is chosen from the electronic database, which causes distance values and arrow markers to appear in the display that indicate the distance and direction to move the telescope. The telescope

196-472: A few specific techniques. Star hopping is a method often used by amateur astronomers with low-tech equipment such as binoculars or a manually driven telescope. It involves the use of maps (or memory) to locate known landmark stars, and "hopping" between them, often with the aid of a finderscope . Because of its simplicity, star hopping is a very common method for finding objects that are close to naked-eye stars. More advanced methods of locating objects in

245-467: A popular telescope mount used in amateur astronomy . Besides the mechanical inability to easily follow celestial motion the altazimuth mount does have other limitations. The telescope's field-of-view rotates at varying speed as the telescope tracks, whilst the telescope body does not, requiring a system to counter-rotate the field of view when used for astrophotography or other types of astronomical imaging. The mount also has blind spot or "zenith hole",

294-422: A small local society located in dark countryside may focus on practical observing and star parties , whereas a large one based in a major city might have numerous members but be limited by light pollution and thus hold regular indoor meetings with guest speakers instead. Major national or international societies generally publish their own academic journal or newsletter, and some hold large multi-day meetings akin to

343-403: A spot near the zenith where the tracking rate in the azimuth coordinate becomes too high to accurately follow equatorial motion (if the elevation is limited to +90 degrees). Alt-alt mounts, or altitude-altitude mounts, are designs similar to horizontal equatorial yoke mounts or Cardan suspension gimbals . This mount is an alternative to the altazimuth mount that has the advantage of not having

392-846: A telescope a great distance away in a dark location. The observer can image through the telescope using CCD cameras. The digital data collected by the telescope is then transmitted and displayed to the user by means of the Internet. An example of a digital remote telescope operation for public use via the Internet is the Bareket observatory , and there are telescope farms in New Mexico, Australia and Atacama in Chile. Amateur astronomers engage in many imaging techniques including film, DSLR , LRGB , and CCD astrophotography . Because CCD imagers are linear, image processing may be used to subtract away

441-424: Is a way for the hobby lovers to share their new sightings and experiences. The popularity of imaging among amateurs has led to large numbers of web sites being written by individuals about their images and equipment. Much of the social interaction of amateur astronomy occurs on mailing lists or discussion groups. Discussion group servers host numerous astronomy lists. A great deal of the commerce of amateur astronomy,

490-469: Is moved until the two angular distance values reach zero, indicating that the telescope is properly aligned. When both the RA and Dec axes are thus "zeroed out", the object should be in the eyepiece. Many DSCs, like go-to systems, can also work in conjunction with laptop sky programs. Computerized systems provide the further advantage of computing coordinate precession. Traditional printed sources are subtitled by

539-409: Is one such example. Amateur astronomers use a range of instruments to study the sky, depending on a combination of their interests and resources. Methods include simply looking at the night sky with the naked eye, using binoculars, and using a variety of optical telescopes of varying power and quality, as well as additional sophisticated equipment, such as cameras, to study light from the sky in both

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588-496: Is possible for amateurs to see them. There are a large number of amateur astronomical societies around the world, that serve as a meeting point for those interested in amateur astronomy. Members range from active observers with their own equipment to "armchair astronomers" who are simply interested in the topic. Societies range widely in their goals and activities, which may depend on a variety of factors such as geographic spread, local circumstances, size, and membership. For example,

637-624: Is searching for overlooked phenomena (e.g., Kreutz Sungrazers ) in the vast libraries of digital images and other data captured by Earth and space based observatories, much of which is available over the Internet. In the past and present, amateur astronomers have played a major role in discovering new comets . Recently however, funding of projects such as the Lincoln Near-Earth Asteroid Research and Near Earth Asteroid Tracking projects has meant that most comets are now discovered by automated systems long before it

686-619: Is sometimes promoted as one of the few remaining sciences for which amateurs can still contribute useful data. To recognize this, the Astronomical Society of the Pacific annually gives Amateur Achievement Awards for significant contributions to astronomy by amateurs. The majority of scientific contributions by amateur astronomers are in the area of data collection. In particular, this applies where large numbers of amateur astronomers with small telescopes are more effective than

735-460: The epoch year , which refers to the positions of celestial objects at a given time to the nearest year (e.g., J2005, J2007). Most such printed sources have been updated for intervals of only about every fifty years (e.g., J1900, J1950, J2000). Computerized sources, on the other hand, are able to calculate the right ascension and declination of the "epoch of date" to the exact instant of observation. GOTO telescopes have become more popular since

784-762: The Landessternwarte Heidelberg-Königstuhl . BESO is a copy of the Fiber-fed Extended Range Optical Spectrograph (FEROS) operated by the European Southern Observatory . Though the HPT has been decommissioned, BESO remains operational, currently mounted on the 1.5-m telescope in OCA. Telescope mount A telescope mount is a mechanical structure which supports a telescope . Telescope mounts are designed to support

833-705: The Poncet Platform . Tilting the polar axis adds a level of complexity to the mount. Mechanical systems have to be engineered to support one or both ends of this axis (such as in fork or yoke mounts). Designs such as German equatorial or cross axis mounts also need large counter weights to counterbalance the mass of the telescope. Larger domes and other structures are also needed to cover the increased mechanical size and range of movement of equatorial mounts. Because of this, equatorial mounts become less viable in very large telescopes and have been pretty much replaced by altazimuth mounts for those applications. Instead of

882-525: The unaided eye , binoculars , or telescopes . Even though scientific research may not be their primary goal, some amateur astronomers make contributions in doing citizen science , such as by monitoring variable stars , double stars , sunspots , or occultations of stars by the Moon or asteroids , or by discovering transient astronomical events , such as comets , galactic novae or supernovae in other galaxies . Amateur astronomers do not use

931-468: The 1980s as technology has improved and prices have been reduced. With these computer-driven telescopes, the user typically enters the name of the item of interest and the mechanics of the telescope point the telescope towards that item automatically. They have several notable advantages for amateur astronomers intent on research. For example, GOTO telescopes tend to be faster for locating items of interest than star hopping, allowing more time for studying of

980-737: The Cassegrain focus; fiber optic coupling was required in most cases. The Hexapod Telescope (HPT) was planned as a prototype for an innovative telescope concept in the 1980s and completed in the 1990s by Krupp Industrietechnik (later Vertex Antennentechnik ) in collaboration with astronomers of the Astronomy Institute of the Ruhr University Bochum (AIRUB) in Germany, led by Prof. Rolf Chini. The Zerodur optics were from Carl Zeiss company at Jena, Germany. The HPT

1029-618: The Earth's rotation allows the objects to cross ( transit ) through that narrow north-south line (the meridian ). This type of mount is used in transit telescopes , designed for precision astronomical measurement. Transit mounts are also used to save on cost or where the instruments mass makes movement on more than one axis very difficult, such as large radio telescopes . Altazimuth, altitude-azimuth, or alt-az mounts allow telescopes to be moved in altitude (up and down), or azimuth (side to side), as separate motions. This mechanically simple mount

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1078-415: The alignment process of telescopes. Setting circles are angular measurement scales that can be placed on the two main rotation axes of some telescopes. Since the widespread adoption of digital setting circles, any classical engraved setting circle is now specifically identified as an "analog setting circle" (ASC). By knowing the coordinates of an object (usually given in equatorial coordinates ),

1127-776: The beginning of the twentieth century, professional astronomy has become an activity clearly distinguished from amateur astronomy and associated activities. Amateur astronomers typically view the sky at night, when most celestial objects and astronomical events are visible, but others observe during the daytime by viewing the Sun and solar eclipses . Some just look at the sky using nothing more than their eyes or binoculars, but more dedicated amateurs often use portable telescopes or telescopes situated in their private or club observatories . Amateurs also join amateur astronomical societies , which can advise, educate or guide them towards ways of finding and observing celestial objects. They also promote

1176-531: The buying and selling of equipment, occurs online. Many amateurs use online tools to plan their nightly observing sessions, using tools such as the Clear Sky Chart . While a number of interesting celestial objects are readily identified by the naked eye, sometimes with the aid of a star chart, many others are so faint or inconspicuous that technical means are necessary to locate them. Although many methods are used in amateur astronomy, most are variations of

1225-404: The classical mounting using two axes , the mirror is supported by six extendable struts ( Stewart-Gough platform ). This configuration allows moving the telescope in all six spatial degrees of freedom and also provides a strong structural integrity. Amateur astronomy Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using

1274-438: The effects of light pollution, which has increased the popularity of astrophotography in urban areas. Narrowband filters may also be used to minimize light pollution. Scientific research is most often not the main goal for many amateur astronomers, unlike professional astronomers. Work of scientific merit is possible, however, and many amateurs successfully contribute to the knowledge base of professional astronomers. Astronomy

1323-403: The entire night sky. A range of astronomy software is also available and used by amateur astronomers, including software that generates maps of the sky, software to assist with astrophotography, observation scheduling software, and software to perform various calculations pertaining to astronomical phenomena. Amateur astronomers often like to keep records of their observations, which usually takes

1372-425: The field of astronomy as their primary source of income or support, and usually have no professional degree in astrophysics or advanced academic training in the subject. Most amateurs are hobbyists, while others have a high degree of experience in astronomy and may often assist and work alongside professional astronomers. Many astronomers have studied the sky throughout history in an amateur framework; however, since

1421-454: The form of an observing log. Observing logs typically record details about which objects were observed and when, as well as describing the details that were seen. Sketching is sometimes used within logs, and photographic records of observations have also been used in recent times. The information gathered is used to help studies and interactions between amateur astronomers in yearly gatherings. Although not professional information or credible, it

1470-418: The hobby of amateur astronomy. Although specialized and experienced amateur astronomers tend to acquire more specialized and more powerful equipment over time, relatively simple equipment is often preferred for certain tasks. Binoculars, for instance, although generally of lower power than the majority of telescopes, also tend to provide a wider field of view , which is preferable for looking at some objects in

1519-669: The mass of the telescope and allow for accurate pointing of the instrument. Many sorts of mounts have been developed over the years, with the majority of effort being put into systems that can track the motion of the fixed stars as the Earth rotates . Fixed telescope mounts are entirely fixed in one position, such as Zenith telescopes that point only straight up and the National Radio Astronomy Observatory 's Green Bank fixed radio ' horn ' built to observe Cassiopeia A . Fixed-altitude mounts usually have

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1568-469: The night sky. Recent models of iPhones have introduced a "night mode " option when taking pictures as well, that allows you to increase exposure, which is a period of time the picture is being taken for. This optimizes focus on light in the frame which is why it is used primarily at night. Amateur astronomers also use star charts that, depending on experience and intentions, may range from simple planispheres through to star atlases with detailed charts of

1617-406: The object. GOTO also allows manufacturers to add equatorial tracking to mechanically simpler alt-azimuth telescope mounts, allowing them to produce an overall less expensive product. GOTO telescopes usually have to be calibrated using alignment stars to provide accurate tracking and positioning. However, several telescope manufacturers have recently developed telescope systems that are calibrated with

1666-410: The primary optics fixed at an altitude angle while rotating horizontally (in azimuth ). They can cover the whole sky but only observe objects for the short time when that object passes a specific altitude and azimuth. Transit mounts are single axis mounts fixed in azimuth while rotating in altitude, usually oriented on a north-south axis. This allows the telescope to view the whole sky, but only when

1715-646: The relatively small number of large telescopes that are available to professional astronomers. Several organizations, such as the American Association of Variable Star Observers and the British Astronomical Association , exist to help coordinate these contributions. Amateur astronomers often contribute toward activities such as monitoring the changes in brightness of variable stars and supernovae , helping to track asteroids , and observing occultations to determine both

1764-590: The science of astronomy among the general public. Collectively, amateur astronomers observe a variety of celestial objects and phenomena. Common targets of amateur astronomers include the Sun , the Moon , planets , stars , comets , meteor showers , and a variety of deep sky objects such as star clusters , galaxies , and nebulae . Many amateurs like to specialise in observing particular objects, types of objects, or types of events which interest them. One branch of amateur astronomy, amateur astrophotography , involves

1813-420: The shape of asteroids and the shape of the terrain on the apparent edge of the Moon as seen from Earth. With more advanced equipment, but still cheap in comparison to professional setups, amateur astronomers can measure the light spectrum emitted from astronomical objects, which can yield high-quality scientific data if the measurements are performed with due care. A relatively recent role for amateur astronomers

1862-406: The six-leg structure allowed for a very precise positioning and repeatability. The HPT could have been rotated ±45° around the optical axis in any position. The mount allowed observations up to 30° elevation. Additionally, by using carbon fiber composites, the HPT was lighter by a factor of ten than classical telescopes of the same aperture. As a result, the ratio of bearing pressure and its own weight

1911-474: The sky include telescope mounts with setting circles , which allow pointing to targets in the sky using celestial coordinates , and GOTO telescopes , which are fully automated telescopes that are capable of locating objects on demand (having first been calibrated). The advent of mobile applications for use in smartphones has led to the creation of many dedicated apps. These apps allow any user to easily locate celestial objects of interest by simply pointing

1960-419: The smartphone device in that direction in the sky. These apps make use of the inbuilt hardware in the phone, such as GPS location and gyroscope . Useful information about the pointed object like celestial coordinates, the name of the object, its constellation, etc. are provided for a quick reference. Some paid versions give more information. These apps are gradually getting into regular use during observing, for

2009-441: The taking of photos of the night sky. Astrophotography has become more popular with the introduction of far easier to use equipment including, digital cameras, DSLR cameras and relatively sophisticated purpose built high quality CCD cameras and CMOS cameras . Most amateur astronomers work at visible wavelengths , but a small minority experiment with wavelengths outside the visible spectrum . An early pioneer of radio astronomy

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2058-518: The telescope to swing in an east-west arc, with a second axis perpendicular to that to allow the telescope to swing in a north-south arc. Slewing or mechanically driving the mount's polar axis in a counter direction to the Earth's rotation allows the telescope to accurately follow the motion of the night sky. Equatorial mounts come in different shapes, include German equatorial mounts (GEM in short), equatorial fork mounts , mixed variations on yoke or cross-axis mounts, and equatorial platforms such as

2107-659: The telescope user can use the setting circle to align (i.e., point) the telescope in the appropriate direction before looking through its eyepiece . A computerized setting circle is called a "digital setting circle" (DSC). Although digital setting circles can be used to display a telescope's RA and Dec coordinates, they are not simply a digital read-out of what can be seen on the telescope's analog setting circles. As with go-to telescopes, digital setting circle computers (commercial names include Argo Navis, Sky Commander, and NGC Max) contain databases of tens of thousands of celestial objects and projections of planet positions. To find

2156-511: The use of built-in GPS, decreasing the time it takes to set up a telescope at the start of an observing session. With the development of fast internet in the last part of the 20th century along with advances in computer controlled telescope mounts and CCD cameras, "remote telescope" astronomy is now a viable means for amateur astronomers not aligned with major telescope facilities to partake in research and deep sky imaging. This enables anyone to control

2205-454: The visual and non-visual parts of the spectrum. To further improve studying the visual and non-visual part of the spectrum, amateur astronomers go to rural areas to get away from light pollution . Commercial telescopes are available, new and used, but it is also common for amateur astronomers to build (or commission the building of) their own custom telescopes. Some people even focus on amateur telescope making as their primary interest within

2254-570: Was Grote Reber , an amateur astronomer who constructed the first purpose-built radio telescope in the late 1930s to follow up on the discovery of radio wavelength emissions from space by Karl Jansky . Non-visual amateur astronomy includes the use of infrared filters on conventional telescopes, and also the use of radio telescopes . Some amateur astronomers use home-made radio telescopes, while others use radio telescopes that were originally built for astronomical research but have since been made available for use by amateurs. The One-Mile Telescope

2303-579: Was thoroughly tested at AIRUB and, in 2006, it was moved to its new location in OCA. The HPT showed great potential for the construction of future very large telescopes, but as it had accumulated several technical problems, and could not be repaired due to a lack of replacement parts, it was decommissioned in 2017. The HPT was equipped with the Bochum Echelle Spectrograph for the Optical (BESO), developed by joint effort of AIRUB and

2352-474: Was used in early telescope designs and until the second half of the 20th century was used as a "less sophisticated" alternative to equatorial mounts since it did not allow tracking of the night sky. This meant until recently it was normally used with inexpensive commercial and hobby constructions. Since the invention of digital tracking systems, altazimuth mounts have come to be used in practically all modern large research telescopes. Digital tracking has also made it

2401-511: Was very high. The active primary mirror had a diameter of 1.5 meters and – with a thickness of only 50 mm – was mounted on 36 piezo actuators. The secondary mirror was also supported by a motorised adjustable hexapod. The disadvantage of the system was that controlling and aiming a hexapod-mounted telescope was much more complex than with conventional telescope mounts. The electromechanical design also allowed only relatively slow travel speeds. The leg structure left very little room for instruments at

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