Editing Astronomical transit (section)

== Missions ==
Since transit photometry allows for scanning large celestial areas with a simple procedure, it has been the most popular and successful form of finding exoplanets in the past decade and includes many projects, some of which have already been retired, others in use today, and some in progress of being planned and created. The most successful projects include HATNet, KELT, Kepler, and WASP, and some new and developmental stage missions such as [[Transiting Exoplanet Survey Satellite|TESS]], HATPI, and others which can be found among the [[List of exoplanet search projects|List of Exoplanet Search Projects]].

=== HATNet ===
[[HATNet Project]] is a set of northern telescopes in [[Fred Lawrence Whipple Observatory]], Arizona and [[Mauna Kea Observatories]], HI, and southern telescopes around the globe, in Africa, Australia, and South America, under the HATSouth branch of the project.<ref>{{Cite web|url=https://hatnet.org/|title=The HATNet Exoplanet Survey|website=hatnet.org|date = 2018|publisher = Princeton University}}</ref> These are small aperture telescopes, just like KELT, and look at a wide field which allows them to scan a large area of the sky for possible transiting planets. In addition, their multitude and spread around the world allows for 24/7 observation of the sky so that more short-period transits can be caught.<ref>{{Cite web|url=https://hatsurveys.org/|title=The HAT Exoplanet Surveys|website=hatsurveys.org|access-date=2018-12-16|archive-date=25 September 2021|archive-url=https://web.archive.org/web/20210925064147/https://hatsurveys.org/|url-status=dead}}</ref>

A third sub-project, HATPI, is currently under construction and will survey most of the night sky seen from its location in Chile.<ref>{{Cite web|url=https://hatpi.org/|title=The HATPI Project|website=hatpi.org|access-date=2018-12-16}}</ref>

=== KELT ===
[[Kilodegree Extremely Little Telescope|KELT]] is a terrestrial telescope mission designed to search for transiting systems of planets of magnitude 8<M<10. It began operation in October 2004 in Winer Observatory and has a southern companion telescope added in 2009.<ref>{{Cite journal|last1=Pepper|first1=J.|last2=Pogge|first2=R.|last3=Depoy|first3=D. L.|last4=Marshall|first4=J. L.|last5=Stanek|first5=K.|last6=Stutz|first6=A.|last7=Trueblood|first7=M.|last8=Trueblood|first8=P.|date=1 July 2007|title=Early Results from the KELT Transit Survey|journal=Transiting Extrapolar Planets Workshop|volume=366|pages=27|bibcode=2007ASPC..366...27P|arxiv=astro-ph/0611947}}</ref> KELT North observes "26-degree wide strip of sky that is overhead from North America during the year", while KELT South observes single target areas of the size 26 by 26 degrees. Both telescopes can detect and identify transit events as small as a 1% flux dip, which allows for detection of planetary systems similar to those in our planetary system.<ref>{{Cite web|url=http://www.astronomy.ohio-state.edu/keltnorth/Method.html|title=KELT-North: Method|website=www.astronomy.ohio-state.edu|access-date=2018-12-16|archive-date=24 January 2019|archive-url=https://web.archive.org/web/20190124180526/http://www.astronomy.ohio-state.edu/keltnorth/Method.html|url-status=dead}}</ref><ref>{{Cite journal|last1=Stassun|first1=Keivan|last2=James|first2=David|last3=Siverd|first3=Robert|last4=Kuhn|first4=Rudolf B.|last5=Pepper|first5=Joshua|date=7 March 2012|title=The KELT-South Telescope|journal=Publications of the Astronomical Society of the Pacific|language=en|volume=124|issue=913|pages=230|doi=10.1086/665044|issn=1538-3873|arxiv=1202.1826|bibcode=2012PASP..124..230P|s2cid=119207060 }}</ref>

=== Kepler / K2 ===

The [[Kepler space telescope]] served the Kepler mission between 7 March 2009 and 11 May 2013, where it observed one part of the sky in search of transiting planets within a 115 square degrees of the sky around the [[Cygnus (constellation)|Cygnus]], [[Lyra]], and [[Draco (constellation)|Draco]] constellations.<ref>{{Cite web|url=http://www.nasa.gov/mission_pages/kepler/overview/index.html|title=Mission overview|last=Johnson|first=Michele|date=13 April 2015|website=NASA|access-date=2018-12-16}}</ref> After that, the satellite continued operating until 15 November 2018, this time changing its field along the ecliptic to a new area roughly every 75 days due to reaction wheel failure.<ref>{{Cite journal|last1=Fortney|first1=Jonathan J.|last2=Twicken|first2=J. D.|last3=Smith|first3=Marcie|last4=Najita|first4=Joan R.|last5=Miglio|first5=Andrea|last6=Marcy|first6=Geoffrey W.|last7=Huber|first7=Daniel|last8=Cochran|first8=William D.|last9=Chaplin|first9=William J.|date=1 April 2014|title=The K2 Mission: Characterization and Early Results|journal=Publications of the Astronomical Society of the Pacific|language=en|volume=126|issue=938|pages=398|doi=10.1086/676406|issn=1538-3873|arxiv=1402.5163|bibcode=2014PASP..126..398H|s2cid=119206652 }}</ref>

=== TESS ===

[[Transiting Exoplanet Survey Satellite|TESS]] was launched on 18 April 2018, and is planned to survey most of the sky by observing it strips defined along the [[right ascension]] lines for 27 days each. Each area surveyed is 27 by 90 degrees. Because of the positioning of sections, the area near TESS's [[Rotation around a fixed axis|rotational axis]] will be surveyed for up to 1 year, allowing for the identification of planetary systems with longer orbital periods.