An observatory is a location used for observing terrestrial, marine, or celestial events.
Astronomy,
climatology/
meteorology,
geophysics,
oceanography and
volcanology are examples of disciplines for which observatories have been constructed. Historically, observatories were as simple as containing an
astronomical sextant (for measuring the distance between
stars) or
Stonehenge (which has some alignments on astronomical phenomena).
Haleakala Observatory at 3,036 m (9,961 ft), Maui, Hawaii
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, 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, 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.[citation needed]
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.[4] This location provides the least atmospheric disturbances and best visibility.[citation needed]
Radio observatories
Beginning in 1933,
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. 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 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.[citation needed]
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 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[5] from the time of its construction during the 1940s until 2009. It has now been surpassed by the new
University of Tokyo Atacama Observatory,[6] an optical-infrared telescope on a remote 5,640 m (18,500 ft) mountaintop in the
Atacama Desert of Chile.
Ancient Indian observatory at Delhi
"El Caracol" observatory temple at
Chichen Itza, Mexico
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 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.[25] Another advantage of space-based telescopes 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.[26] 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 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 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.[citation needed]
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 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.[27]
^"ALMA's Solitude". Picture of the Week. ESO. Retrieved 26 December 2012.
^Chaisson, Eric; McMillan, Steve (2002). Astronomy Today, Fourth Edition.
Prentice Hall. pp. 116–119.
^Chaisson, Eric; McMillan, Steve (2002). Astronomy Today, Fourth Edition.
Prentice Hall. p. 119.
^Saunders, Will; Lawrence, Jon S.; Storey, John W. V.; Ashley, Michael C. B.; Kato, Seiji; Minnis, Patrick; Winker, David M.; Liu, Guiping & Kulesa, Craig (2009). "Where Is the Best Site on Earth? Domes A, B, C, and F, and Ridges A and B". Publications of the Astronomical Society of the Pacific. 121 (883): 976–992.
arXiv:0905.4156.
Bibcode:
2009PASP..121..976S.
doi:
10.1086/605780.
S2CID11166739.
^Kennedy, Edward S. (1962). "Review: The Observatory in Islam and Its Place in the General History of the Observatory by Aydin Sayili". Isis. 53 (2): 237–239.
doi:
10.1086/349558.
Aubin, David; Charlotte Bigg, and
H. Otto Sibum, eds. The Heavens on Earth: Observatories and Astronomy in Nineteenth-Century Science and Culture (Duke University Press; 2010) 384 pages; Topics include astronomy as military science in Sweden, the
Pulkovo Observatory in the Russia of
Czar Nicholas I, and physics and the astronomical community in late 19th-century America.
Brunier, Serge, et al. Great Observatories of the World (2005)
Gressot Julien and Jeanneret Romain, « Determining the right time, or the establishment of a culture of astronomical precision at Neuchâtel Observatory in the mid-19th century », Journal for the History of Astronomy, 53(1), 2022, 27–48,
https://doi.org/10.1177/00218286211068572
Leverington, David. Observatories and Telescopes of Modern Times - Ground-Based Optical and Radio Astronomy Facilities since 1945. Cambridge University Press, Cambridge 2016,
ISBN9780521899932.