Difference between revisions 1733608 and 1735221 on enwikiversity

[[Image:Skylab-73-HC-440HR.jpg|thumb|right|200px|The Saturn V SA-513 lifts off to boost the Skylab Orbital Workshop into Earth orbit on March 14, 1973. Credit: NASA.]]
[[Astronomy]] is performed by location and is subject to local conditions. The shapes and sizes of observatories have changed over time, as have their altitude. The motivations for putting an observatory manned or unmanned at different altitudes has led to a great variety in '''lofting technology'''.
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'''Def.''' an organization of knowledge for the practical purpose of propelling high into the air or above the air is called '''lofting technology'''.

==Observatories==
{{main|Astronomy/Observatories|Observatories}}
'''Def.''' "[a] place where stars, planets and other [[wikt:celestial body|celestial bodies]] are observed"<ref name=Observatory
Wikt>{{ cite web
|title=observatory, In: ''Wiktionary''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=October 16,
|year=2012
|url=http://en.wiktionary.org/wiki/observatory
|accessdate=2012-12-05 }}</ref> is called an '''observatory'''.

==Horizontal coordinate system==
{{main|Coordinates/Horizontals|Horizontal coordinate systems}}
[[Image:Horizontal coordinate system 2.svg|thumb|right|200px|This diagram describes altitude and azimuth. Credit: Francisco Javier Blanco González.]]
The altitude of an entity in the sky is given by the angle of the arc from the local horizon to the entity.

“The horizontal coordinate system is a [[w:celestial coordinate system|celestial coordinate system]] that uses the observer's local [[w:horizon|horizon]] as the [[w:Fundamental plane (spherical coordinates)|fundamental plane]]. This coordinate system divides the sky into the upper [[w:sphere|hemisphere]] where objects are visible, and the lower hemisphere where objects cannot be seen since the earth is in the way. The [[w:Great circle|great circle]] separating hemispheres [is] called [the] celestial horizon or rational horizon. The pole of the upper hemisphere is called the [[w:Zenith|zenith]]. The pole of the lower hemisphere is called the [[w:Nadir|nadir]].  <ref name=Schombert>{{ cite web
|url=http://abyss.uoregon.edu/~js/ast121/lectures/lec03.html
|title=Earth Coordinate System
|author=James Schombert
|publisher=University of Oregon Department of Physics
|accessdate=19 March 2011 }}</ref>”<ref name=Horizontal>{{ cite journal
|title=Horizontal coordinate system⏎
|journal=, In: Wikipedia
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=April 20,
|year=2012
|url=http://en.wikipedia.org/wiki/Horizontal_coordinate_system
|accessdate=2012-05-14 }}</ref>

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*'''[[w:Density altitude|Density altitude]]''' -- altitude in terms of the density of the air”<ref name=Altitude/>.
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==Altitude regions==
{{main|Locations/Earth/Altitudes|Altitudes}}
The [[w:Earth's atmosphere|Earth's atmosphere]] is divided into altitude regions:<ref name=NWS>{{ cite web
| title=Layers of the Atmosphere
⏎
|work=, In: ''JetStream, the National Weather Service Online Weather School''
| publisher=National Weather Service
| url=http://www.srh.noaa.gov/srh/jetstream/atmos/layers.htm
| accessdate=22 December 2005 }}</ref>
* [[w:Troposphere|Troposphere]] &mdash; surface to 8,000 m at the poles &ndash; 18,000 m at the [[w:equator|equator]], ending at the Tropopause.
* [[w:Stratosphere|Stratosphere]] &mdash; Troposphere to 50 km
* [[w:Mesosphere|Mesosphere]] &mdash; Stratosphere to 85 km
* [[w:Thermosphere|Thermosphere]] &mdash; Mesosphere to 675 km
(contracted; show full) (geology)|crustal]] thickness causes gravity to vary on the surface, so that the mean sea level will differ from the ellipsoid. This difference is the ''[[w:geoid|geoid]] height'', positive above or outside the ellipsoid, negative below or inside. The geoid height variation is under 110 m on Earth. The geoid height can change abruptly due to earthquakes (such as the [[w:2004 Indian Ocean earthquake|Sumatra-Andaman earthquake]]) or reduction in ice masses (such as [[Greenland]]).<ref
>[ name=Grace>{{ cite web
|url=http://www.spaceref.com/news/viewpr.html?pid=18567  ⏎
|title=NASA's Grace Finds Greenland Melting Faster, 'Sees' Sumatra Quake], December 20, 2005, ⏎
|month=20 December
|year=2005
|publisher=Goddard Space Flight Center. }}</ref>”<ref name=EarthRadius>{{ cite web
|title=Earth radius, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 5,
|year=2012
|url=http://en.wikipedia.org/wiki/Earth_radius
|accessdate=2012-12-05 }}</ref>
(contracted; show full)|title=Relation of ELF Noise and Schumann Resonances to Thunderstorm Activity, In: ''Planetary Electrodynamics''
|publisher=Gordon & Breach
|location=
|month=
|year=1969
|editor=Coroniti SC, Hughes J.
|pages=55-83
|url=
https://books.google.com/books?hl=en&lr=&id=wDXzhyskXOgC&oi=fnd&pg=PA55&ots=WeVGMuJPyf&sig=oy6kFVKrttABgfZ99meyM6rbXgg
|arxiv=
|bibcode=
|doi=
|pmid=
|isbn=
|accessdate=2012-12-08 }}</ref><ref name=Hill>{{ cite journal
|author=RD Hill
|title=Spherical capacitor hypothesis of the Earth's electric field
|journal=Pure and Applied Geophysics
|month=November-December
|year=1971
|volume=84
|issue=1
|pages=67-74
|url=http://link.springer.com/article/10.1007/BF00875454
|arxiv=
|bibcode=
|doi=10.1007/BF00875454
|pmid=
|accessdate=2012-12-08 }}</ref> relative to the positively charged ionosphere. There is a constant flow of electricity, at around 1350 amperes (A), and resistance of the Earth's atmosphere is around 220 Ohms.<ref name=Farrell>{{ cite journal
|author=WM Farrell, MD Desch
|title=Is there a Martian atmospheric electric circuit?
|journal=Journal of Geophysical Research
|month=April
|year=2001
|volume=106
|issue=E4
|pages=7591-5
|url=http://onlinelibrary.wiley.com/doi/10.1029/2000JE001271/full
|arxiv=
|bibcode=
|doi=10.1029/2000JE001271
|pmid=
|accessdate=2012-12-08 }}</ref> This gives a power output of around 400 megawatts (MW), which is ultimately regenerated by the power of the Sun that affects the ionosphere, as well as the troposphere, causing thunderstorms. The electrical energy stored in the Earth's atmosphere is around 150 gigajoules (GJ).

The Earth-ionosphere system acts as a giant capacitor, of capacity 1.8 Farads.

The Earth's surface carries around -1 nC of electric charge per square meter.

==Stonehenge==
[[Image:Stonehenge.jpg|thumb|left|200px|[[w:Stonehenge|Stonehenge]] is a [[w:Neolithic|Neolithic]] monument that may have functioned as a celestial observatory. 102.8 masl. Credit: [[commons:User:Wigulf|Wigulf]].]]
“Whatever religious, mystical or spiritual elements were central to Stonehenge, its design includes a celestial observatory function, which might have allowed prediction of eclipse, solstice, equinox and other celestial events important to a contemporary religion.<ref name=Hawkins>{{ cite book
| author=GS Hawkins
| year=1966
| title = Stonehenge Decoded
|url=https://www.biblio.com/stonehenge-decoded-by-hawkins-gerald-s/work/59753
|publisher=Souvenir Press
|location=Cambridge⏎
| isbn= 978-0880291477 }}</ref>”<ref name=Stonehenge>{{ cite web
|title=Stonehenge, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=November 20,
|year=2012
|url=http://en.wikipedia.org/wiki/Stonehenge
|accessdate=2012-12-05 }}</ref>

“Stonehenge does not occupy a topographic high, but rather a site of intermediate elevation, such that the natural horizon, when viewed from the heel stone, is remarkably even and is sufficiently far away that its elevation above the astronomical horizon is a small angle.”<ref name=Robinson>{{ cite journal
|author=J. H. Robinson
|title=Evidence Concerning Stonehenge as an “Observatory”
|journal=Bulletin of the American Astronomical Society
|month=March
|year=1984
|volume=16
|issue=3
|pages=449
|url=
|arxiv=
|bibcode=1984BAAS...16..449R
|doi=
|pmid=
|accessdate=2012-02-07 }}</ref>

“All results were registered by Professor Gowland in relation to a datum line [102.8 m] 337.4 feet above sea level.”<ref name=Lockyer>{{ cite book
|author=Morman Lockyer
|title=Stonehenge and Other British Stone Monuments Astronomically Considered
|publisher=Kessinger Publishing
|location=
|month=
|year=2003
|editor=
|pages=516
|url=https://archive.org/details/stonehengeandot00lockgoog
|arxiv=
|bibcode=
|doi=
|pmid=
|isbn=
|accessdate=2012-02-07 }}</ref>
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==Giza Pyramids==
[[Image:All Gizah Pyramids.jpg|right|thumb|250px|The pyramids of Giza. Credit: [http://liberato.org Ricardo Liberato].]]
“The Great Pyramid stands on the northern edge of the Giza Plateau, [60.4 m] 198 feet above sea level”.<ref name=Nikolic>{{ cite book
|author=Petko Vidusa Nikolic, Petko Nikolic Vidusa
|title=The Great Pyramid and the Bible : Earth's Measurements
|publisher=Mystik Book
|location=Kitchener, Canada
|month=
|year=2005
|editor=
|pages=65
|url=https://www.amazon.com/Great-Pyramid-Bible-Earths-Measurements/dp/0973237147
|arxiv=
|bibcode=
|doi=
|pmid=
|isbn=0973237147
|accessdate=2012-02-08 }}</ref>

“Since the first modern measurements of the precise cardinal orientations of the pyramids by [[w:Flinders Petrie|Flinders Petrie]], various astronomical methods have been proposed for the original establishment of these orientations.<ref>Belmonte 2001</ref><ref>Neugebauer 1980</ref> It was recently proposed that this was done by observing the positions of two stars in [[w:Ursa Major|the Plough / Big Dipper]] which was known to Egyptians as the thigh. It is thought that a vertical alignment between these two stars checked with a [[w:plumb bob|plumb bob]] was used to ascertain where North lay. The deviations from true North using this model reflect the accepted dates of construction.<ref>Spence 2000</ref> Some have argued that the pyramids were laid out as [[w:Graham Hancock#Orion Correlation Theory|a map of the three stars]]  in the belt of Orion,<ref>Hancock 1996:168</ref> although this theory has been criticized by reputable astronomers.<ref name="Fairall">Fairall 1999</ref><ref name="Krupp">Krupp 1997b name=Belmonte>{{cite journal|author=Belmonte, J. A.|date=2001|title= On the Orientation of Old Kingdom Egyptian Pyramids|journal= Archaeoastronomy: Supplement to the Journal for the History of Astronomy|volume=32 | issue = 26|pages=S1–S20|bibcode = 2001JHAS...32....1B }}</ref><ref name=Neugebauer>{{cite journal|last= Neugebauer|first= Otto| authorlink= Otto Neugebauer|title= On the Orientation of Pyramids|journal= [[Centaurus (journal)|Centaurus]]| volume= 24| pages= 1–3| date= 1980|doi= 10.1111/j.1600-0498.1980.tb00362.x |bibcode = 1980Cent...24....1N }}</ref> It was recently proposed that this was done by observing the positions of two stars in [[w:Ursa Major|the Plough / Big Dipper]] which was known to Egyptians as the thigh. It is thought that a vertical alignment between these two stars checked with a [[w:plumb bob|plumb bob]] was used to ascertain where North lay. The deviations from true North using this model reflect the accepted dates of construction.<ref name=Spence>{{cite journal|author=Spence, K|date=16 November 2000|title=Ancient Egyptian Chronoology and the astronomical orientation of the pyramids |journal=Nature |volume= 408|pages=320–324 |doi=10.1038/35042510 |pmid=11099032 |issue=6810|bibcode = 2000Natur.408..320S }}</ref> Some have argued that the pyramids were laid out as [[w:Graham Hancock#Orion Correlation Theory|a map of the three stars]] in the belt of Orion,<ref name=Hancock>{{cite book|author=Hancock, G|date=1996|title=Fingerprints of the Gods|publisher=New York: Three Rivers Press|isbn=0-517-88729-0}}</ref> although this theory has been criticized by reputable astronomers.<ref name="Fairall">{{cite journal|author=Fairall, A. |authorlink=Anthony Patrick Fairall |date=1999 |url=http://www.antiquityofman.com/Orion_Fairall.html |title=Precession and the layout of the Ancient Egyptian pyramids |journal=[[Astronomy & Geophysics]] |publisher=The Royal Astronomical Society |volume=40 |issue=4 |accessdate=2008-03-22 |url=https://web.archive.org/web/20080228144915/http://www.antiquityofman.com/Orion_Fairall.html |archivedate=2008-02-28 }}</ref><ref name="Krupp">{{cite journal|author=Krupp, E.C. |authorlink=Ed Krupp |title=Rambling Through the Skies: Pyramid Marketing SchemesPyramid Marketing Schemes |journal=Sky and Telescope |date=February 1997 |url=http://www.antiquityofman.com/Krupp_pyramid_marketing_schemes.html |volume=94 |issue=2 |pages=64}}</ref>”<ref name=Archaeoastronomy>{{ cite web
|title=Archaeoastronomy, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=December 5,
|year=2012
|url=http://en.wikipedia.org/wiki/Archaeoastronomy
|accessdate=2012-12-05 }}</ref>
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| author=Alfred Krabbe
| title=SOFIA telescope, In: ‘’Proceedings of SPIE: Astronomical Telescopes and Instrumentation’’
| pages=276–281
| date=March, 2007
| publisher=SPIE — The International Society for Optical Engineering
| location=Munich, Germany

|url=https://arxiv.org/abs/astro-ph/0004253⏎
| arxiv=astro-ph/0004253 }}</ref> The aircraft can also travel to almost any point on the Earth's surface, allowing observation from the northern and southern hemispheres."<ref name=StratosphericObservatoryforInfraredAstronomy>{{ cite web
|title=Stratospheric Observatory for Infrared Astronomy, In: ''Wikipedia''
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=November 23,
|year=2012
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[[Image:Ariane42P rocket.gif|thumb|right|200px|The ERS-2 is carried into a sun-synchronous polar orbit by an Ariane 4 similar to the one imaged. Credit: NASA.]]
"A '''Sun-synchronous orbit''' (sometimes called a heliosynchronous orbit<ref name="shcherbakova">Shcherbakova, N. N.; Beletskij, V. V.; Sazonov, V. V. - Kosmicheskie Issledovaniia, Tom 37, No. 4, p. 417 - 427,
 see ⏎
|url=http://adsabs.harvard.edu/abs/1999KosIs..37..417S</ref>) is a [[w:geocentric orbit|geocentric orbit]] which combines [[w:altitude|altitude]] and [[w:inclination|inclination]] in such a way that an object on that orbit ascends or descends over any given Earth latitude at the same local [[w:mean solar time|mean solar time]]. The surface [[w:illumination angle|illumination angle]] will be nearly the same every time. This consistent lighting is a useful characteristic for satellites that image the Earth&#(contracted; show full)
|publisher=Wikimedia Foundation, Inc
|location=San Francisco, California
|month=November 8,
|year=2012
|url=http://en.wikipedia.org/wiki/STS-45
|accessdate=2012-12-05 }}</ref>.

"The '''Shuttle Radar Topography Mission''' ('''SRTM''') is an international research effort that obtained [[w:digital elevation model|digital elevation model]]s on a near-global scale from 56°&nbsp;S to 60°&nbsp;N,<ref name=NikP2>{{
Harvnb|Nikolakopoulos|2006|p=2cite journal|last1=Nikolakopoulos |first1=K. G. |last2=Kamaratakis |first2=E. K |last3=Chrysoulakis |first3=N. |date=10 November 2006 |title=SRTM vs ASTER elevation products. Comparison for two regions in Crete, Greece |journal=International Journal of Remote Sensing |volume=27 |issue=21 |issn=0143-1161 |url=http://www.iacm.forth.gr/_docs/pubs/4/Nikolakopoulos_et_al_2006.pdf |accessdate=March 10, 2010 |deadurl=yes |archiveurl=https://web.archive.org/web/20110721081314/http://www.iacm.forth.gr/_docs/pubs/4/Nikolakopoulos_et_al_2006.pdf |archivedate=July 21, 2011 }}</ref> to generate the most complete high-resolution digital topographic database of Earth prior to the release of the [[w:ASTER GDEM|ASTER GDEM]] in 2009. SRTM consisted of a specially modified radar system that flew on board the [[w:Space Shuttle|Space Shuttle]] [[w:Space Shuttle Endeavour|Endeavour]] during the 11-day [[w:STS-99|STS-99]] mission in February 2000, based on the older ''Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar'' (SIR-C/X-SAR), previously used on(contracted; show full)[[Category:Astronomy/Lectures]]
[[Category:Astrophysics/Lectures]]
[[Category:History/Lectures]]
[[Category:Radiation astronomy/Lectures]]
[[Category:Resources last modified in October 2016]]
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