View source for Occultation

{{Short description|When an object is hidden behind another}}
{{hatnote group|
{{Distinguish|Occult}}
{{For|the Shia Islamic belief|Occultation (Islam)}}
}}
[[File:Occultation.jpg|thumb|200px|In this July 1997 still frame captured from video, the bright star [[Aldebaran]] has just reappeared on the dark limb of the waning [[Lunar phase|crescent moon]] in this predawn occultation.]]

An '''occultation''' is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in [[astronomy]], but can also refer to any situation in which an object in the foreground blocks from view (occults) an object in the background. In this general sense, occultation applies to the visual scene observed from low-flying aircraft (or [[computer-generated imagery]]) when foreground objects obscure distant objects dynamically, as the scene changes over time.

If the closer body does not entirely conceal the farther one, the event is called a ''[[Transit (astronomy)|transit]]''. Both transit and occultation may be referred to generally as ''occlusion''; and if a shadow is cast onto the observer, it is called an [[eclipse]].

The symbol for an occultation, and especially a [[solar eclipse]], is [[file:Occultation symbol.svg|🝵]] (U+1F775 🝵).{{Not verified in body|date=November 2024}}

== Occultations by the Moon ==
{{distinguish|Lunar eclipse}}
[[File:UranusAndMoon 20221108 fromJP.jpg|left|thumb|232x232px|Occultation of [[Uranus]] during the [[November 2022 lunar eclipse|lunar eclipse]] on 8 November 2022.]]
[[File:Occultation.ogv|thumb|Occultation of a star by the Moon.|230x230px]]

The term occultation is most frequently used to describe '''lunar occultations''', those relatively frequent occasions when the [[Moon]] passes in front of a [[star]] during the course of its orbital motion around the Earth. Since the Moon, with an [[angular speed]] with respect to the stars of 0.55 [[Minute of arc#Symbols, abbreviations and subdivisions|arcsec]]/s or 2.7 μrad/s, has a very thin atmosphere and stars have an [[Angular diameter#Use in astronomy|angular diameter]] of at most 0.057 [[arcsecond]]s or 0.28 μrad, a star that is occulted by the Moon will disappear or reappear in 0.1 seconds or less on the Moon's edge, or limb. Events that take place on the Moon's dark limb are of particular interest to observers, because the lack of glare allows easier observation and timing.

The Moon's orbit is inclined slightly with respect to the [[ecliptic]] {{Crossreference|(see [[orbit of the Moon]])}} meaning any star with an [[ecliptic latitude]] between –6.6 and +6.6 degrees may be occulted by it.<ref>{{cite journal | first=Jean | last=Meeus | title=La périodicité des occultations | journal=Ciel et Terre | volume=87 | year=1971 | pages=240–252 | bibcode=1972LAstr..86..141M }} – English translation in: {{cite book | first=Jean | last=Meeus | chapter=Series of occultations | title=Mathematical Astronomy Morsels | publication-place=Richmond | publisher=Willmann-Bell | year=1997 | pages=113–124 }}</ref> Three first magnitude stars appear well within that band – [[Regulus]], [[Spica]], and [[Antares]] – meaning they may be occulted by the Moon or by planets.<ref name="planets">{{cite web |title=Occultations of bright stars by planets between 0 and 4000 |url=http://www.pierpaoloricci.it/dati/occpiastelle_eng.htm |access-date=2005-06-16}}</ref> Occultations of [[Aldebaran]] are in this epoch only possible by the Moon, because the planets pass Aldebaran to the north. Neither planetary nor lunar occultations of [[Pollux (star)|Pollux]] are currently possible, however several thousand years ago lunar occultations were possible. Some notably close [[deep-sky object]]s, such as the [[Pleiades]], can be occulted by the Moon.

[[File:OccultJupiter 6-7-2005 6-07PM Nelson NZ.jpg|thumb|200px|Jupiter (the bright object in the upper right) a few minutes before being occulted by the Moon on 16 June 2005.]]

[[file:Saturn_Occultation.gif|thumb|Occultation of the planet Saturn by the Moon on 3 November 2001.|left|239x239px]]

[[File:Total_Solar_Eclipse_-_April_8,_2024_-_Mazatlan_Mexico_-_Ten_Minute_Time_Lapse_v2_1080p.webm|thumb|Ten Minute [[Time-lapse_photography|Time Lapse]] Video of the [[Solar_eclipse_of_April_8,_2024|Total Solar Eclipse on April 8, 2024]], in [[Mazatlán]], [[Mexico]].]]

Within a few kilometres of the edge of an occultation's predicted path, referred to as its northern or southern limit, an observer may see the star intermittently disappearing and reappearing as the irregular limb of the Moon moves past the star, creating what is known as a ''[[grazing lunar occultation]]''. From an observational and scientific standpoint, these "grazes" are the most dynamic and interesting of lunar occultations.

The accurate timing of lunar occultations is performed regularly by (primarily amateur) astronomers. Lunar occultations timed to an accuracy of a few tenths of a second have various scientific uses, particularly in refining our knowledge of [[lunar topography]]. Photoelectric analysis of lunar occultations have also discovered some stars to be very close visual or spectroscopic [[binary star|binaries]]. Some angular diameters of stars have been measured by timing of lunar occultations, which is useful for determining [[effective temperature]]s of those stars. Early radio astronomers found occultations of radio sources by the Moon valuable for determining their exact positions, because the long wavelength of radio waves limited the resolution available through direct observation. This was crucial for the unambiguous identification of the radio source [[3C 273]] with the optical quasar and its jet,<ref name="HazardMackeyShimmins63" /> and a [[fundamental astronomy|fundamental]] prerequisite for [[Maarten Schmidt]]'s discovery of the cosmological nature of [[quasars]].

Several times during the year the Moon can be seen occulting a planet.<ref>{{cite web |last1=The International Occultation Timing Association (IOTA) |title=Bright Planet & Asteroid Occultations by the Moon for 2021 |url=http://www.lunar-occultations.com/iota/planets/planets.htm |access-date=10 November 2021}}</ref> Since planets, unlike stars, have significant angular sizes, lunar occultations of planets will create a narrow zone on Earth from which a partial occultation of the planet will occur. An observer located within that narrow zone could observe the planet's disk partly blocked by the slowly moving Moon. The same mechanism can be seen with the Sun, where observers on Earth will view it as a [[solar eclipse]]. Therefore, a total solar eclipse is essentially the Moon occulting the Sun.

== Occultation by planets ==
[[File:Dione Rhea Occultation.jpg|thumb|200px|A grazing occultation of [[Rhea (moon)|Rhea]] by [[Dione (moon)|Dione]], two [[moons of Saturn]], imaged by ''[[Cassini–Huygens]]''.]]
{{main|Planetary transits and occultations}}

Stars may also be occulted by planets. Occultations of bright stars are rare. In 1959, [[Venus]] occulted [[Regulus]], and the next occultation of a bright star (also Regulus by Venus) will be in 2044.<ref name="planets"/> [[Uranus]]'s [[Rings of Uranus|rings]] were first discovered when that planet occulted a star in 1977. On 3 July 1989, [[Saturn]] passed in front of the 5th magnitude star [[Sagittarius (constellation)|28 Sagittarii]]. [[Pluto]] occulted stars in 1988, 2002, and 2006, allowing its tenuous atmosphere to be studied via [[atmospheric limb sounding]].

In rare cases, one planet can pass in front of another.<ref>Albers, Steven, "Mutual Occultations of Planets: 1557–2230", ''Sky and Telescope'', March 1979</ref> If the nearer planet appears larger than the more distant one, the event is called a mutual planetary occultation. The last occultation or transit occurred on 3 January 1818 and the next will occur on 22 November 2065, in both cases involving the same two planets—[[Venus]] and [[Jupiter]].<ref>{{cite web |url=http://www.pierpaoloricci.it/dati/occpia_eng.htm |title=OCCULTATIONS BETWEEN PLANETS FROM THE YEAR 0 TO 4000 |p=Cielo Ed I Suoi Fenomeni |author=Pierpaolo Ricci |access-date=2025-02-21 }}</ref>

[[Jupiter]] rarely occults [[Saturn]]. This is one of the rarest events known,<ref>{{Cite web |url=http://climate.gi.alaska.edu/curtis/astro4.html |title=Chapter 2: Predictable Non-periodic Events – Part II |access-date=9 August 2012 |archive-date=13 August 2012 |archive-url=https://web.archive.org/web/20120813234832/http://climate.gi.alaska.edu/Curtis/astro4.html |url-status=dead }}</ref> with the next occurrence on February 10, 7541. This event is visible worldwide since the duo would be positioned almost in opposition to the sun, in the border line between the constellations of [[Orion (constellation)|Orion]] and [[Taurus (constellation)|Taurus]]. In some areas this occultation cannot be seen, but when viewed through even small telescopes, both gas giants appear to be in the same part of view through the eyepiece. The last one occurred in 6857 B.C.E.<ref>{{cite web|author=Bob King | url=https://skyandtelescope.org/astronomy-news/jupiter-and-saturn-embrace-in-solstice-conjunction/ |title=Jupiter and Saturn Embrace in Solstice Conjunction |publisher=Sky & Telescope|date=December 20, 2020}}</ref>

=={{anchor|Occultations by asteroids}} Occultations by smaller bodies ==

A further set of [[#top|occultation]]s are those when a [[small Solar System body]] or [[dwarf planet]] passes in front of a star, temporarily blocking its light as seen from Earth.<ref name="MIT" /> These occultations are useful for measuring the size and position of body much more precisely than can be done by other means. A cross-sectional profile of the shape of a body can even be determined if a number of observers at different, nearby, locations observe the occultation. Occultations have been used to calculate the diameter of [[trans-Neptunian object]]s such as {{mpl-|55636|2002 TX|300}}, [[28978 Ixion|Ixion]] and [[20000 Varuna|Varuna]]. Software for coordinating observations is available for download at http://www.occultwatcher.net/

In addition, '''mutual occultation and eclipsing events''' can occur between a primary and its [[Minor-planet moon|satellite]]. A [[Minor-planet moon#List of minor planets with moons|large number of moons]] have been discovered analyzing the photometric [[light curve]]s of small bodies and detecting a second, superimposed brightness variation, from which an [[orbital period]] for the satellite (secondary), and a secondary-to-primary diameter-ratio (for the [[Binary asteroid|binary system]]) can often be derived.

=== Examples ===
{| class=wikitable style="font-size: 0.9em; margin-left: 0.6em" align="right"
|+ Notable occultations of asteroids
!Name!![[Chord (astronomy)|Chords]]!!Measured<br />profile (km)
|-
|[[704 Interamnia]]||35||350×304
|-
|[[39 Laetitia]]||~16||219×142
|-
|[[94 Aurora]]||9||225×173
|-
|[[375 Ursula]]||6||216±10
|-
|[[444 Gyptis]]||6||179×150
|-
|[[48 Doris]]||4||278×142
|}

==== Asteroids ====
* On 29 May 1983, [[2 Pallas]] occulted the naked-eye bright [[spectroscopic binary]] star [[1 Vulpeculae]] along a track across the southern United States, northern Mexico, and north parts of the Caribbean. Observations from 130 different locations defined the shape of about two-thirds of the asteroid, and detected the secondary companion of the bright binary star; these observations, taken together with those of a separate occultation by Pallas in 1979, provided a complete figure for the asteroid eight years before any asteroid was visited by a spacecraft (the much smaller [[951 Gaspra|Gaspra]] by [[Galileo spacecraft|Galileo]] in October 1991).<ref name=Dunham45/>
* On 12 March 2009 nine asteroids ([[85&nbsp;Io]], [[247&nbsp;Eukrate]], [[1585&nbsp;Union]], [[201&nbsp;Penelope]], [[70&nbsp;Panopaea]], [[980&nbsp;Anacostia]], [[2448&nbsp;Sholokhov]], [[1746&nbsp;Brouwer]], and [[191&nbsp;Kolga]]) occulted notable magnitude stars, viewed from given places on the Earth.<ref name=Preston/>
* According to the 1998 European Asteroidal Occultation Results from Euraster, [[39&nbsp;Laetitia]] was observed by over 38 observatories in one occultation on 3 March 1998, which resulted in many [[Chord (astronomy)|chords]] being determined.<ref name=euraster />
* The star [[Regulus]] was occulted by the asteroid [[163&nbsp;Erigone]] in the early morning of 20 March 2014.<ref name=IOTA2006 /> This was the brightest occultation of an asteroid ever predicted to occur over a populated area. As the [[main belt asteroid]] passed in front of the star its {{convert|100|km|mi|sigfig=1|abbr=on}} shadow swept across [[Nassau County, New York|Nassau]] and Suffolk counties, all of New York City and the [[Hudson River Valley]], with the center of the shadow path following a line roughly connecting New York City, White Plains, Newburgh, Oneonta, Rome, and Pulaski before crossing into Canada near Belleville and [[North Bay, Ontario]].<ref name=IOTA2006/><ref name=Solex/> Bad weather obscured the occultation.<ref>{{cite web |url=http://occultations.org/regulus2014/ |title=Volunteer observers invited to time the March 20, 2014 Occultation of Regulus |access-date=3 October 2014 |archive-date=27 August 2017 |archive-url=https://web.archive.org/web/20170827122732/http://occultations.org/Regulus2014/ |url-status=dead }}</ref>
* The star [[Betelgeuse]] was partially occulted by the asteroid [[319&nbsp;Leona]] in the early morning of 12 December 2023. The event could only be viewed over a small strip of America, Europe, and Asia.<ref>{{Cite web |title=OccultWatcher Cloud |url=https://cloud.occultwatcher.net/event/1075-319-83995-648466-H27989/1246616 |access-date=2025-03-13 |website=cloud.occultwatcher.net}}</ref><ref>{{Cite web |title=Observations of the Occultation of Betelgeuse by (319) Leona – IOTA/ES |url=https://call4obs.iota-es.de/observations-of-the-occultation-of-betelgeuse-by-319-leona |access-date=2025-03-13 |language=en-GB}}</ref>

[[File:The occultation of dwarf planet Makemake on 23 April 2011.ogv|thumb|This animation shows the path of the shadow of the dwarf planet [[Makemake (dwarf planet)|Makemake]] during an occultation of a faint star in April 2011. Note: the actual shape of the shadow on Earth will not be exactly round as shown here. This video is to illustrate the phenomenon.]]

==== Distant objects ====
* Preliminary results of a 6 November 2010 occultation by the dwarf planet [[Eris (dwarf planet)|Eris]] of a [[apparent magnitude|magnitude]] 17 star ([http://www.wikisky.org/?ra=1.6527583999999989&de=-4.353371999999999&zoom=10&show_grid=1&show_constellation_lines=1&show_constellation_boundaries=1&show_const_names=0&show_galaxies=1&show_box=1&box_ra=1.6527584&box_de=-4.353372&box_width=50&box_height=50&img_source=DSS2 USNOA2 0825-00375767]) in the [[constellation]] of [[Cetus (constellation)|Cetus]] placed an upper limit on Eris's diameter of 2320&nbsp;km, making it almost the same size as Pluto.<ref name=occult /> Due to their slower movement through the night sky, occultations by [[Trans-Neptunian object|TNO]]s are far less common than by asteroids in the main-belt.
* The dwarf planet [[Haumea]] was observed in a stellar transit on 21 January 2017, identifying a ring.<ref name=Haumeaocc/>
* On 3 June 2017, a star was occulted by the Kuiper belt object [[486958 Arrokoth]], the first such occultation detected.<ref name="First KBO Occultation" /> The multi-faceted campaign involved cooperation from the Argentinian government (including local governments – a major highway was closed for two hours, and street lights were turned off, in order to preclude light pollution), three spacecraft, 24 portable ground-based telescopes, and NASA's SOFIA airborne observatory in "the most challenging stellar occultation in the history of astronomy," in an effort spanning six months.<ref name="NASA's New Horizons Team Strikes Gold in Argentina">{{Cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20170719 |title=NASA's New Horizons Team Strikes Gold in Argentina |date=2017-07-19 |website=New Horizons: NASA's Mission to Pluto}}</ref>

== Double occultations ==

The Moon or another celestial body can occult multiple celestial bodies at the same time.

Because of its relatively large [[angular diameter]] the Moon, at any given time, occults an indeterminate number of stars and galaxies. However the Moon occulting (obscuring) two bright objects (e.g. two planets or a bright star and a planet) simultaneously is extremely rare and can be seen only from a small part of the world: the last such event was on 23 April 1998, when it occulted Venus and Jupiter for observers on [[Ascension Island]].

== Artificial occultations ==

The ''Big Occulting Steerable Satellite (BOSS)'' was a proposed [[satellite]] that would work in conjunction with a [[telescope]] to detect [[planet]]s around distant stars. The satellite consists of a large, very lightweight sheet, and a set of maneuvering thrusters and navigation systems. It would maneuver to a position along the line of sight between the telescope and a nearby star. The satellite would thereby block the radiation from the star, permitting the orbiting planets to be observed.<ref name="Copi-2000" />

The proposed satellite would have a dimension of {{convert|70|x|70|m|ft}}, a mass of about 600&nbsp;kg, and maneuver by means of an [[ion drive]] engine in combination with using the sheet as a light sail. Positioned at a distance of 100,000&nbsp;km from the telescope, it would block more than 99.998% of the starlight.

There are two possible configurations of this satellite. The first would work with a [[space telescope]], most likely positioned near the [[Earth]]'s L<sub>2</sub> [[Lagrangian point]]. The second would place the satellite in a highly elliptical orbit about the Earth, and work in conjunction with a ground telescope. At the [[apogee]] of the orbit, the satellite would remain relatively stationary with respect to the ground, allowing longer exposure times.

An updated version of this design is called the [[Starshade]], which uses a [[sunflower]]-shaped [[coronagraph]] disc. A comparable proposal was also made for a satellite to occult bright X-ray sources, called an ''X-ray Occulting Steerable Satellite'' or XOSS.<ref>{{cite web |url=http://hea.cwru.edu/xoss/ |title=The X-ray Occulting Steerable Satellite (XOSS) |publisher=CASE |access-date=2007-02-09 |archive-url=https://web.archive.org/web/20110719183026/http://hea.cwru.edu/xoss/ |archive-date=19 July 2011 |url-status=dead }}</ref>

== See also ==
{{div col|colwidth=20em}}
* [[Astronomical transit]] (also for occultations of planets by other planets)
* [[Conjunction_(astronomy)|Conjunction]]
* [[GPS occultation]]
* [[Grazing lunar occultation]]
* [[Grazing occultation]]
* [[List of minor planets]]
* [[List of Solar System objects by size]]
* [[Lunar occultation of Venus]]
* [[Occultations, transits, and eclipses]]
* [[Planetary transits and occultations]]
* [[Radio occultation]]
* [[Solar eclipse]]
* [[Syzygy (astronomy)]]
* [[TAOS: The Taiwanese-American Occultation Survey]]
* [[Transit of Mercury]]
* [[Transit of Venus]]
{{div col end}}

== References ==
{{Reflist|refs=

<ref name="HazardMackeyShimmins63">{{cite journal
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<ref name="MIT">{{cite web
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 |access-date=2009-10-26}}</ref> Several events occur nearly every day over the world. From any particular place such events occur almost every night, although most require a [[telescope]] to see. Professionals and amateurs around the globe are collaborating over the Internet to exchange their observation for a joint analysis.<ref name=Preston>{{cite web
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<ref name=euraster>{{cite web
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 }} [https://euraster.ericfrappa.com/results/1998/19980321-Laetitia-cbf.gif (Chords)] {{Webarchive|url=https://web.archive.org/web/20110723121134/http://www.euraster.net/results/1998/19980321-Laetitia-cbf.gif |date=23 July 2011 }}</ref>

<ref name=IOTA2006>{{cite web
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}}</ref> as first predicted by A. Vitagliano in 2004.<ref name=Solex>{{cite web
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<ref name=Dunham45>{{cite journal |bibcode=1990AJ.....99.1636D |title=The Size and Shape of (2) Pallas from the 1983 Occultation of 1 Vulpeculae |last1=Dunham |first1=D. W. |last2=Dunham |first2=J. B. |last3=Binzel |first3=R. P. |last4=Evans |first4=D. S. |last5=Freuh |first5=M. |last6=Henry |first6=G. W. |last7=a'Hearn |first7=M. F. |last8=Schnurr |first8=R. G. |last9=Betts |first9=R. |last10=Haynes |first10=H. |last11=Orcutt |first11=R. |last12=Bowell |first12=E. |last13=Wasserman |first13=L. H. |last14=Nye |first14=R. A. |last15=Giclas |first15=H. L. |last16=Chapman |first16=C. R. |last17=Dietz |first17=R. D. |last18=Moncivais |first18=C. |last19=Douglass |first19=W. T. |last20=Parker |first20=D. C. |last21=Beish |first21=J. D. |last22=Martin |first22=J. O. |last23=Monger |first23=D. R. |last24=Hubbard |first24=W. B. |last25=Reitsema |first25=H. J. |last26=Klemola |first26=A. R. |last27=Lee |first27=P. D. |last28=McNamara |first28=B. R. |last29=Maley |first29=P. D. |last30=Manly |first30=P. |journal=[[The Astronomical Journal]] |date=1990 |volume=99 |page=1636 |doi=10.1086/115446 |display-authors=1 }}</ref>

<ref name=Haumeaocc>{{cite journal |bibcode=2017Natur.550..219O |title=The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation |last1=Ortiz |first1=J. L. |last2=Santos-Sanz |first2=P. |last3=Sicardy |first3=B. |last4=Benedetti-Rossi |first4=G. |last5=Bérard |first5=D. |last6=Morales |first6=N. |last7=Duffard |first7=R. |last8=Braga-Ribas |first8=F. |last9=Hopp |first9=U. |last10=Ries |first10=C. |last11=Nascimbeni |first11=V. |last12=Marzari |first12=F. |last13=Granata |first13=V. |last14=Pál |first14=A. |last15=Kiss |first15=C. |last16=Pribulla |first16=T. |last17=Komžík |first17=R. |last18=Hornoch |first18=K. |last19=Pravec |first19=P. |last20=Bacci |first20=P. |last21=Maestripieri |first21=M. |last22=Nerli |first22=L. |last23=Mazzei |first23=L. |last24=Bachini |first24=M. |last25=Martinelli |first25=F. |last26=Succi |first26=G. |last27=Ciabattari |first27=F. |last28=Mikuz |first28=H. |last29=Carbognani |first29=A. |last30=Gaehrken |first30=B. |journal=Nature |date=2017 |volume=550 |issue=7675 |pages=219–223 |doi=10.1038/nature24051 |pmid=29022593 |arxiv=2006.03113 |display-authors=1 }}</ref>

<ref name=occult>{{cite web |title=The shadowy hand of Eris |website=Mike Brown's Planets |first=Mike |last=Brown |date=2010 |url=http://www.mikebrownsplanets.com/2010/11/shadowy-hand-of-eris.html |access-date=2010-11-07}}</ref>

<ref name="First KBO Occultation">{{Cite web |url=https://www.nasa.gov/feature/new-mysteries-surround-new-horizons-next-flyby-target |title=New Mysteries Surround New Horizons' Next Flyby Target: NASA's New Horizons spacecraft doesn't zoom past its next science target until New Year's Day 2019, but the Kuiper Belt object, known as 2014 MU69, is already revealing surprises. |date=2017-07-05 |publisher=NASA |access-date=20 July 2017 |archive-date=21 July 2017 |archive-url=https://web.archive.org/web/20170721232423/https://www.nasa.gov/feature/new-mysteries-surround-new-horizons-next-flyby-target/ |url-status=dead }}</ref>

<ref name="Copi-2000">{{cite journal |first1=C. J. |last1=Copi |first2=G. D. |last2=Starkman |title=The Big Occulting Steerable Satellite (BOSS) |journal=The Astrophysical Journal |date=2000 |volume=532 |issue=1 |pages=581–592 |bibcode=2000ApJ...532..581C |doi=10.1086/308525 |arxiv=astro-ph/9904413|s2cid=18790887 }}</ref>

}} <!-- end of reflist -->

== Further reading ==
* {{Cite book |last=Meeus |first=Jean |title=Astronomical Tables of the Sun, Moon and Planets |location=Richmond, Virginia |publisher=Willmann-Bell, Inc |date=1995 |isbn=0-943396-45-X}}
* {{in lang|de}} [http://www.marco-peuschel.de Marco Peuschel] – Astronomische Tabellen für den Mond von 2007 bis 2016, Mondphasen, Apsiden, Knotendurchgänge, Maximale und minimale Deklinationswerte und Sternbedeckungen sowie ausführliche Ephemeriden für jeden Tag des Jahres, inkl. Mondauf-und Untergänge und physische Daten.

== External links ==
{{Sister project links|wikt=occultation|commons=Category:Occultation}}
* [http://www.stellaroccultations.info Occultation Studies at Williams College] {{Webarchive|url=https://web.archive.org/web/20210117025531/http://www.stellaroccultations.info/ |date=17 January 2021 }}, www.stellaroccultations.info
* [http://www.occultations.org/ International Occultation Timing Association (IOTA)], with [https://web.archive.org/web/20181209184743/http://www.lunar-occultations.com/iota/iotandx.htm lunar occultations]
* [http://www.occultations.net/ Moon, planets, asteroid occultations], www.occultations.net
* [http://astroclub.tau.ac.il/ephem/PlanetsConj/ Mutual occultations (and conjunctions) of planets] {{Webarchive|url=https://web.archive.org/web/20110711061917/http://astroclub.tau.ac.il/ephem/PlanetsConj/ |date=11 July 2011 }}, TAU astronomy Club
* [http://stevealbers.net/albers/ast/conjun/conjun.html Planetary Conjunctions and Mutual Planetary Occultations] stevealbers.net
* [http://www.space.com/scienceastronomy/060814_tno_found.html Discovery Hints at a Quadrillion Space Rocks Beyond Neptune], www.space.com, August 2006
* [http://starrymirror.com/planetaryoccultations.htm Scientists Use Novel Technique To Watch Occultations By Planets] {{Webarchive|url=https://web.archive.org/web/20181031173944/http://starrymirror.com/planetaryoccultations.htm |date=31 October 2018 }}, ''The Starry Mirror'', 2007
* [http://www.asteroidoccultation.com/ Asteroid Occultation Updates], www.asteroidoccultation.com, 2018
* [http://www.occultations.net/occultations-asteroids.htm Occultations by Phoebe], www.occultations.net
* [https://arxiv.org/abs/1104.4227 Combining asteroid models derived by lightcurve inversion with asteroidal occultation silhouettes], arXiv, 2011
* [http://www.pierpaoloricci.it/dati/occpiastelle_eng.htm Occultations of bright stars by planets between 0 and 4000], ''Il cielo ed i suoi femomeni'' {{in lang|it}}
* [https://web.archive.org/web/20170709162133/http://www.doa-site.nl/index.html Lunar Occultation Workbench], (software), Durch Occultation Association
* [https://web.archive.org/web/20181226095648/http://www.lunar-occultations.com/iota/occult4.htm Occult], (software), www.lunar-occultations.com

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