Editing Eclipse (section)

==Other planets and dwarf planets==

===Gas giants===
{{see also|Solar eclipses on Jupiter|Solar eclipses on Saturn|Solar eclipses on Uranus|Solar eclipses on Neptune}}
[[Image:JupiterandIo.jpg|thumb|right|A picture of [[Jupiter]] and its moon [[Io (moon)|Io]] taken by [[Hubble Space Telescope|Hubble]]. The black spot is Io's shadow.]]
[[Image:Saturn eclipse.jpg|250px|right|thumb|[[Saturn]] occults the Sun as seen from the ''[[Cassini–Huygens]]'' space probe]]
The [[gas giant]] planets have many moons and thus frequently display eclipses. The most striking involve [[Jupiter]], which has four large moons and a low [[axial tilt]], making eclipses more frequent as these bodies pass through the shadow of the larger planet. Transits occur with equal frequency. It is common to see the larger moons casting circular shadows upon Jupiter's cloudtops.

The eclipses of the [[Galilean moon]]s by Jupiter became accurately predictable once their orbital elements were known. During the 1670s, it was discovered that these events were occurring about 17 minutes later than expected when Jupiter was on the far side of the Sun. [[Ole Rømer]] deduced that the delay was caused by the time needed for light to travel from Jupiter to the Earth. This was used to produce the first estimate of the [[speed of light]].<ref>{{cite web
 |url         = http://www.mathpages.com/home/kmath203/kmath203.htm
 |title       = Roemer's Hypothesis
 |publisher   = MathPages
 |access-date  = 2007-01-12
 |url-status     = live
 |archive-url  = http://archive.wikiwix.com/cache/20110224015233/http://www.mathpages.com/home/kmath203/kmath203.htm
 |archive-date = 2011-02-24
}}</ref>

The timing of the Jovian satellite eclipses was also used to calculate an observer's [[longitude]] upon the Earth. By knowing the expected time when an eclipse would be observed at a standard longitude (such as [[Greenwich]]), the time difference could be computed by accurately observing the local time of the eclipse. The time difference gives the longitude of the observer because every hour of difference corresponded to 15° around the Earth's equator. This technique was used, for example, by [[Giovanni Domenico Cassini|Giovanni D. Cassini]] in 1679 to re-map [[France]].<ref>{{cite journal
 |last        = Cassini
 |first       = Giovanni D.
 |author-link  = Giovanni Domenico Cassini
 |title       = Monsieur Cassini His New and Exact Tables for the Eclipses of the First Satellite of Jupiter, Reduced to the Julian Stile, and Meridian of London
 |journal     = [[Philosophical Transactions of the Royal Society]]
 |date        = 1694
 |volume      = 18
 |issue       = 207–214
 |pages       = 237–256
 |doi         = 10.1098/rstl.1694.0048
 |jstor       = 102468
 |doi-access= free
 |bibcode = 1694RSPT...18..237C
 }}</ref>

On the other three [[gas giant]]s ([[Saturn]], [[Uranus]] and [[Neptune]]) eclipses only occur at certain periods during the planet's orbit, due to their higher [[inclination]] between the orbits of the moon and the [[orbital plane (astronomy)|orbital plane]] of the planet. The moon [[Titan (moon)|Titan]], for example, has an orbital plane tilted about 1.6° to Saturn's equatorial plane. But Saturn has an axial tilt of nearly 27°. The orbital plane of Titan only crosses the line of sight to the Sun at two points along Saturn's orbit. As the orbital period of Saturn is 29.7&nbsp;years, an eclipse is only possible about every 15 years.

===Mars===
{{main|Transit of Phobos from Mars}}
[[Image:PIA05553.gif|right|thumbnail|[[Transit of Phobos from Mars]], as seen by the Mars ''[[Opportunity (rover)|Opportunity rover]]'' (10 March 2004).]]
On [[Mars]], only partial solar eclipses ([[Transit of Phobos from Mars|transits]]) are possible, because neither of its moons is large enough, at their respective orbital radii, to cover the Sun's disc as seen from the surface of the planet. Eclipses of the moons by Mars are not only possible, but commonplace, with hundreds occurring each Earth year. There are also rare occasions when Deimos is eclipsed by Phobos.<ref>{{cite book 
|first=Norman |last=Davidson |date=1985 
|title=Astronomy and the Imagination: A New Approach to Man's Experience of the Stars 
|publisher=Routledge 
|isbn=978-0-7102-0371-7 }}</ref> Martian eclipses have been photographed from both the surface of Mars and from orbit.

===Pluto===
{{main|Solar eclipses on Pluto}}
[[Pluto]], with its proportionately largest moon [[Charon (moon)|Charon]], is also the site of many eclipses. A series of such mutual eclipses occurred between 1985 and 1990.<ref>{{cite journal 
|last=Buie |first=M. W. |author2=Polk, K. S. 
|title=Polarization of the Pluto-Charon System During a Satellite Eclipse 
|journal=Bulletin of the American Astronomical Society 
|date=1988 |volume=20 |page=806 
|bibcode=1988BAAS...20..806B }}</ref> These daily events led to the first accurate measurements of the physical parameters of both objects.<ref>{{cite journal |last=Tholen |first=D. J. |author2=Buie, M. W. |author3=Binzel, R. P. |author4=Frueh, M. L. |title=Improved Orbital and Physical Parameters for the Pluto-Charon System |journal=Science |date=1987 |volume=237 |issue=4814 |pages=512&ndash;514 |doi=10.1126/science.237.4814.512 |pmid=17730324 |bibcode=1987Sci...237..512T |s2cid=33536340 }}</ref>

===Mercury and Venus===
Eclipses are impossible on [[Mercury (planet)|Mercury]] and [[Venus]], which have no moons. However, as seen from the Earth, both have been observed to [[Astronomical transit|transit]] across the face of the Sun. [[Transit of Venus|Transits of Venus]] occur in pairs separated by an interval of eight years, but each pair of events happen less than once a century.<ref>{{cite web |last=Espenak |first=Fred |date=May 29, 2007 |url=http://sunearth.gsfc.nasa.gov/eclipse/transit/transit.html |title=Planetary Transits Across the Sun |publisher=NASA |access-date=2008-03-11 |url-status=dead |archive-url=https://web.archive.org/web/20080311033452/http://sunearth.gsfc.nasa.gov/eclipse/transit/transit.html |archive-date=March 11, 2008 }}</ref> According to NASA, the next pair of Venus transits will occur on December 10, 2117, and December 8, 2125. [[Transit of Mercury|Transits of Mercury]] are much more common, occurring 13 times each century, on average.<ref>{{Cite web|url=https://eclipse2017.nasa.gov/when-will-next-transits-mercury-and-venus-occur-during-total-solar-eclipse|title=When will the next transits of Mercury and Venus occur during a total solar eclipse? {{!}} Total Solar Eclipse 2017|website=eclipse2017.nasa.gov|language=en|access-date=2017-09-25|url-status=dead|archive-url=https://web.archive.org/web/20170918151937/https://eclipse2017.nasa.gov/when-will-next-transits-mercury-and-venus-occur-during-total-solar-eclipse|archive-date=2017-09-18}}</ref>