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46-702: The City Observatory was an astronomical observatory on Calton Hill in Edinburgh , Scotland. It is also known as the Calton Hill Observatory . The site is enclosed by a boundary wall with a monument to John Playfair , president of the Edinburgh Astronomical Institution , in the southeast corner. The oldest part is the Gothic Tower in the southwest corner, facing Princes Street and Edinburgh Castle . It

92-717: A 12-foot (3.7 m, focal length ) reflecting telescope made by his late brother James Short . He intended to open a public observatory on Calton Hill as a commercial enterprise. However, in 1736 Colin Maclaurin , professor of mathematics at the University of Edinburgh , had collected funds for a university observatory. Due to the Porteous Riots and the Jacobite rising of 1745 the funds were left unused. These were made available to build Short's observatory; and

138-702: A large percentage of clear nights per year, dry air, and are at high elevations. At high elevations, the Earth's atmosphere is thinner, thereby minimizing the effects of atmospheric turbulence and resulting in better astronomical " seeing ". 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

184-424: A measurement of stellar parallax), and eventually he was beaten to the punch by Friedrich Wilhelm Bessel , who published a parallax of 10.3 light years (9.6% too small) for 61 Cygni in 1838. Henderson published his results in 1839, but was relegated to second place because of his lack of confidence. He later published confirming observations by Thomas Maclear . Alpha Centauri remained the nearest known star until

230-582: A new City Observatory was created on Calton Hill toward the end of the 19th century. The 6-inch (15 cm) Cooke refractor was donated by William McEwan and installed in the dome on the Playfair Building. Additional domes were built for a 13-inch (33 cm) reflector donated by Robert Cox and for a 13-inch (33 cm) refractor transferred from the Dunecht observatory near Aberdeen. Only remnants of these two domes remain today. The City Dome

276-520: A particular subject (such as public health observatory ) or for a particular geographic area ( European Audiovisual Observatory ). Astronomical observatories are mainly divided into four categories: space-based , airborne , ground-based, and underground-based. Historically, ground-based observatories were as simple as containing an astronomical sextant (for measuring the distance between stars ) or Stonehenge (which has some alignments on astronomical phenomena). Ground-based observatories, located on

322-635: A posthumous letter recommended to the Admiralty that Henderson take his place. Henderson was passed over for that position, but the recommendation was enough to get him a position at the Royal Observatory at the Cape of Good Hope in South Africa . There he made a considerable number of stellar observations between April 1832 and May 1833, including those for which he is remembered today. It

368-596: A remote 5,640 m (18,500 ft) mountaintop in the Atacama Desert of Chile. The oldest proto-observatories, in the sense of an observation post for astronomy, The oldest true observatories, in the sense of a specialized research institute , include: Space-based observatories are telescopes or other instruments that are located in outer space , many in orbit around the Earth. Space telescopes can be used to observe astronomical objects at wavelengths of

414-629: A scheme designed by architectural firm Collective Architecture . In 2014, Collective relocated from their gallery in Cockburn Street, Edinburgh , opened an exhibition in the City Dome and received an award of £900,000 from Creative Scotland to further develop the site. After a £4.5 million development, in 2018 Collective re-opened the City Observatory site as Collective, a contemporary art centre and restaurant. New exhibition space

460-463: A second – a popular and commercial rather than scientific – observatory elsewhere on Calton Hill. In 1850 this was removed and she moved to Castle Hill, where her enterprise eventually became today's Camera Obscura on the Royal Mile . In 1812 the observatory was handed over to the Edinburgh Astronomical Institution , which opened its popular observatory in the Gothic Tower. In 1818 work began on

506-419: A week at the absolute reference point calibration measurements are performed. Example magnetic observatories include: Example seismic observation projects and observatories include: Example gravitational wave observatories include: A volcano observatory is an institution that conducts the monitoring of a volcano as well as research in order to understand the potential impacts of active volcanism. Among

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552-833: Is a facility which precisely measures the total intensity of Earth's magnetic field for field strength and direction at standard intervals. Geomagnetic observatories are most useful when located away from human activities to avoid disturbances of anthropogenic origin, and the observation data is collected at a fixed location continuously for decades. Magnetic observations are aggregated, processed, quality checked and made public through data centers such as INTERMAGNET . The types of measuring equipment at an observatory may include magnetometers (torsion, declination-inclination fluxgate, proton precession, Overhauser-effect), variometer (3-component vector, total-field scalar), dip circle , inclinometer , earth inductor, theodolite , self-recording magnetograph, magnetic declinometer, azimuth compass. Once

598-444: Is a scientific institution whose main task is to make observations in the fields of meteorology, geomagnetism and tides that are important for the navy and civil shipping. An astronomical observatory is usually also attached. Some of these observatories also deal with nautical weather forecasts and storm warnings, astronomical time services, nautical calendars and seismology. Example marine observatories include: A magnetic observatory

644-471: Is also known as Observatory House, the Old Observatory, or after its designer James Craig House. The central building with the appearance of a Greek temple is the Playfair Building, named after the building's designer William Henry Playfair . This houses the 6-inch (15 cm) refractor in its dome and the 6.4-inch (16 cm) transit telescope in its eastern wing. The largest dome of the site

690-582: Is buried in Greyfriars Kirkyard . The grave may be either in the grave of Alexander Adie or in a grave marked by the stone "to his memory". His name is not recorded on the Adie grave; Adie himself died 14 years after Henderson. A blue plaque is installed on his house at 1 Hillside Crescent. It refers to him as "Thomas J. A. Henderson", similar to middle names wrongly added to Misplaced Pages around 2007. A larger memorial (naming him "Thomas Henderson")

736-658: Is that, because of their location above the Earth's atmosphere, their images are free from the effects of atmospheric turbulence that plague ground-based observations. As a result, the angular 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 extremely difficult to maintain. The Hubble Space Telescope

782-613: Is the Mauna Kea Observatory , located near the summit of a 4,205 m (13,796 ft) volcano in Hawaiʻi. The Chacaltaya Astrophysical Observatory in Bolivia, at 5,230 m (17,160 ft), was the world's highest permanent astronomical observatory from the time of its construction during the 1940s until 2009. It has now been surpassed by the new University of Tokyo Atacama Observatory , an optical-infrared telescope on

828-399: Is the City Dome in the northeast corner. During the early 20th century this contained a 22-inch (56 cm) refractor. In 2018, the entire site was restored and new buildings were added. The City Observatory site was opened freely to the public for the first time on 24 November 2018 as Collective , a centre for contemporary art. In 1776 Thomas Short returned to Edinburgh , bringing with him

874-552: The Astronomical Society of Edinburgh was formed with Field as first president. Peck and Ralph Sampson , the then Astronomer Royal for Scotland , were honorary presidents. Field died in 1937; and in 1938 the observatory was leased to the Society, which ran the City Observatory until vandalism and theft of roofing material rendered the site unusable in 2009. In 2009 the Astronomical Society of Edinburgh moved out of

920-484: The City of Edinburgh provided a plot of land on Calton Hill. The observatory was to be open to university students. James Craig designed the observatory, which, under Robert Adam 's influence, was to look like a fortification with a wall and Gothic towers at its corners. The city controlled the building project, but the money ran out after only the first of the towers was built. Short moved into this as residence and ran

966-478: The Stratospheric Observatory for Infrared Astronomy use airplanes to observe in the infrared , which is absorbed by water vapor in the atmosphere. High-altitude balloons for X-ray astronomy have been used in a variety of countries. Example underground, underwater or under ice neutrino observatories include: Example meteorological observatories include: A marine observatory

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1012-405: The meridian were observed and used to keep the observatory clock , a sidereal clock manufactured by Robert Bryson , accurate . Accurate time was important for navigation , and mariners would bring ships' chronometers from the port of Leith up to Calton Hill for adjustment. In 1854 the time ball was installed on Nelson's Monument next to the observatory and visible from the port. This

1058-461: The transit telescope . Fraunhofer had made the lens, but after his death it fell to Repsold – and after his death to Repsold's son – to complete and install the instrument. In 1834 Thomas Henderson took up the position of observer. This was now the post of Astronomer Royal for Scotland and Regius Professor of Astronomy in the University of Edinburgh . Until his death in 1844 he worked on Calton Hill. In 1839 he published his results regarding

1104-642: The City Observatory and the buildings reverted to the City of Edinburgh Council. The Council renovated Observatory House and the interior was restored by the Vivat Trust (a charity which aims to preserve old buildings) who let it as holiday accommodation. However Vivat went into liquidation in 2015. After being unoccupied for several years, in 2012 the Council started a programme to renovate the remaining buildings in partnership with visual arts charity Collective in

1150-542: The English journalist William Jerdan , naturalist and oceanographer Edward Forbes , F.R.S. and his "The Red Lions", a dining club for younger members of the British Association, (named after the tavern where the first meeting was held), had occasion to run up to the observatory of Calton Hill for astronomical studies. The main purpose of the observatory was a time service . The transits of stars through

1196-768: The Hillside shows art by artists in Scotland who have never previously shown their work in a major exhibition while the restored City Dome is host to works by international artists. William Playfair's Observatory has been restored according to his surviving plans and the original Transit instrument is now on public display. Observatory House was given a £400,000 renovation in 2021 and was offered for short term lets by Collective. Astronomical observatory The term observatoire has been used in French since at least 1976 to denote any institution that compiles and presents data on

1242-556: The Playfair Building. Designed by William Henry Playfair this was to become the scientific observatory of the Institution. Following a loyal address to George IV in 1822 this became the Royal Observatory . Again the funds proved insufficient, so that the purchase of instruments and the employment of an observer depended on funding from the Government. After much delay the instrumentation was completed in 1831 with delivery of

1288-631: The US, Roque de los Muchachos Observatory in Spain, and Paranal Observatory and Cerro Tololo Inter-American 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 central part of Eastern Antarctica. This location provides the least atmospheric disturbances and best visibility. Beginning in 1933, radio telescopes have been built for use in

1334-806: The best known are the Hawaiian Volcano Observatory and the Vesuvius Observatory . Mobile volcano observatories exist with the USGS VDAP (Volcano Disaster Assistance Program), to be deployed on demand. Each volcano observatory has a geographic area of responsibility it is assigned to whereby the observatory is tasked with spreading activity forecasts, analyzing potential volcanic activity threats and cooperating with communities in preparation for volcanic eruption . Thomas James Henderson Thomas Henderson FRSE FRS FRAS (28 December 1798 – 23 November 1844)

1380-716: The discovery of Proxima Centauri in 1915 by Robert T. A. Innes . In the meantime, his measurement work at the Cape had led him to be appointed the first Astronomer Royal for Scotland in 1834. The vacant chair of astronomy at the University of Edinburgh was given to him on the advice of Prime Minister Lord Melbourne . From 1834 he worked at the City Observatory (then called the Calton Hill Observatory) in Edinburgh until his death. In April, 1840 he

1426-553: The distance of alpha Centauri based on observations he had made 1832/33 at the Royal Observatory, Cape of Good Hope . In 1846 Charles Piazzi Smyth became second Astronomer Royal for Scotland and set about reducing and publishing the backlog of Henderson's observations. In 1847 the Astronomical Institution – having run out of money – handed the Royal Observatory over to the Government. According to

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1472-463: The electromagnetic spectrum that cannot penetrate the Earth's atmosphere and are thus impossible to observe using ground-based telescopes. The Earth's atmosphere is opaque to ultraviolet radiation, X-rays , and gamma rays and is partially opaque to infrared radiation so observations in these portions of the electromagnetic spectrum are best carried out from a location above the atmosphere of our planet. Another advantage of space-based telescopes

1518-406: The entire 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,

1564-670: The field of radio astronomy to observe the Universe in the radio portion of the electromagnetic spectrum. Such an instrument, or collection of instruments, with supporting facilities such as control centres, visitor housing, data reduction centers, and/or maintenance facilities are called radio observatories . Radio observatories are similarly located far from major population centers to avoid electromagnetic interference (EMI) from radio , TV , radar , and other EMI emitting devices, but unlike optical observatories, radio observatories can be placed in valleys for further EMI shielding. Some of

1610-401: The observatory until his death in 1788. An actual observatory, smaller than originally planned, was also built where the Playfair Building is now. After Short's death the observatory was kept going by his family for a while, then leased to opticians and finally abandoned around 1807. The site reverted to the city. Short's daughter Maria Theresa Short was to return to Edinburgh in 1827. She ran

1656-401: The observatory's equipment had become largely obsolete. Also, the site had originally not been chosen through scientific investigation and its proximity to the city was causing problems. In 1896 the Royal Observatory moved to a new site on Blackford Hill . The Calton Hill Observatory, once again, reverted to the City of Edinburgh . In the wake of the Royal Observatory moving to Blackford Hill,

1702-461: The profession as an assistant to a variety of nobles. However, his major hobbies were astronomy and mathematics, and after coming up with a new method for using lunar occultation to measure longitude he came to the attention of Thomas Young , superintendent of the Royal Navy 's "Nautical Almanac". Young helped the young Henderson enter the larger world of astronomical science, and on his death

1748-414: 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, to protect the delicate instruments from the elements. 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,

1794-795: The world's major radio observatories include the Very Large Array in New Mexico , United States, Jodrell Bank in the UK , Arecibo in Puerto Rico , Parkes in New South Wales , Australia, and Chajnantor in Chile . A related discipline is Very-long-baseline interferometry (VLBI). Since the mid-20th century, a number of astronomical observatories have been constructed at very high altitudes , above 4,000–5,000 m (13,000–16,000 ft). The largest and most notable of these

1840-535: Was a Scottish astronomer and mathematician noted for being the first person to measure the distance to Alpha Centauri , the major component of the nearest stellar system to Earth, the first to determine the parallax of a fixed star, and for being the first Astronomer Royal for Scotland . Born in Dundee , he was educated at the High School of Dundee , after which he trained as a lawyer, working his way up through

1886-483: Was able to be serviced by the Space Shuttles 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 Earth's atmosphere. They also have an advantage over space telescopes: The instruments can be deployed, repaired and updated much more quickly and inexpensively. The Kuiper Airborne Observatory and

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1932-479: Was built to house a 22-inch (56 cm) refractor. This did not perform very well and was dismantled in 1926. The dome remained and was used as a lecture theatre. The observatory opened in 1898 with William Peck as City Astronomer. Peck had previously been observer at Cox's observatory in Murrayfield . After Peck's death in 1925 his assistant John McDougal Field continued to run the City Observatory. In 1924

1978-551: Was controlled by electrical pulses from the observatory clock. A few years later the One O'Clock Gun on Edinburgh Castle was added. This was also controlled through an electrical wire, spanning the city from Calton Hill to the Castle. Today the time ball and One O' Clock Gun are tourist attractions. They are no longer controlled from a state of the art clock, but are triggered "by hand". By 1888, when Smyth resigned, through underfunding

2024-737: Was elected a Fellow of the Royal Society . Henderson became a member or fellow of several distinguished societies, including the Royal Astronomical Society (1832) and the Royal Society of Edinburgh (1834). He married Alexander Adie 's daughter Janet Mary Adie (1808–1842) in 1836 and had one daughter, Janet Mary Jane Henderson (1842–1893) who is buried in the Grange Cemetery . He died at home 1 Hillside Crescent in Edinburgh on 23 November 1844 and

2070-483: Was pointed out to him by Manuel John Johnson of the East India Company's observatory on Saint Helena that the bright southern star Alpha Centauri had a large proper motion , and Henderson concluded that it might be relatively close. The 1830s version of the "space race" was to be the first person to measure the distance to a star using parallax , a task which is easier the closer the star. Henderson

2116-509: Was thus in a good position to be this person. After retiring back to the United Kingdom due to bad health, he began analysing his measurements and eventually came to the conclusion that Alpha Centauri was just slightly less than one parsec away, 3.25 light years . This figure is reasonably accurate, being 25.6% too small. Henderson did not immediately publish his results, however (there had been previous, discredited attempts to claim

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