Solar eclipse

For the video game, seeSolar Eclipse(video game).For the song, seeSolar Eclipse (song).

"Eclipse of the Sun" redirects here. For other uses, seeEclipse of the Sun (disambiguation).

Atotal solar eclipseoccurs when the Moon completely covers the Sun's disk.Solar prominencescan be seen along the limb (in red) as well as extensively thecoronaland partly the radiatingcoronal streamers.(August 11, 1999)

Anannular solar eclipseoccurs when the Moon is too far away to completely cover the Sun's disk (October 14, 2023).

During apartial solar eclipse,the Moon blocks only part of the Sun's disk (October 25, 2022).

Asolar eclipseoccurs when theMoonpasses betweenEarthand theSun,thereby obscuring the view of the Sun from a small part of Earth, totally or partially. Such an alignment occurs approximately every six months, during theeclipse seasonin itsnew moonphase, when the Moon's orbital plane is closest tothe plane of Earth's orbit.In a totaleclipse,the disk of the Sun is fully obscured by the Moon. Inpartial and annular eclipses,only part of the Sun is obscured. Unlike alunar eclipse,which may be viewed from anywhere on thenightside of Earth, a solar eclipse can only be viewed from a relatively small area of the world. As such, although total solar eclipses occur somewhere on Earth every 18 months on average, they recur at any given place only once every 360 to 410 years.

If the Moon were in a perfectly circular orbit and in the same orbital plane as Earth, there would be total solar eclipses once a month, at every new moon. Instead, because the Moon's orbit istiltedat about 5 degrees to Earth's orbit, its shadow usually misses Earth. Solar (and lunar) eclipses therefore happen only duringeclipse seasons,resulting in at least two, and up to five, solar eclipses each year, no more than two of which can be total.Total eclipses are rarer because they require a more precise alignment between the centers of theSunandMoon,and because the Moon'sapparent sizein the sky is sometimes too small to fully cover the Sun.

An eclipse is anatural phenomenon.In some ancient and modern cultures, solar eclipses were attributed tosupernaturalcauses or regarded as badomens.Astronomers' predictions of eclipses began in China as early as the 4th century BC; eclipses hundreds of years into the future may now be predicted with high accuracy.

Looking directly at the Suncan lead to permanent eye damage, so special eye protection or indirect viewing techniques are used when viewing a solar eclipse. Only the total phase of a total solar eclipse is safe to view without protection. Enthusiasts known aseclipse chasersor umbraphiles travel to remote locations to see solar eclipses.

Types

Ten Minute Time Lapse Video of the Total Solar Eclipse on April 8, 2024, inMazatlán,Mexico.

Partial and annular phases of thesolar eclipse of May 20, 2012

The Sun's distance from Earth is about 400 times the Moon's distance, and the Sun'sdiameteris about 400 times the Moon's diameter. Because these ratios are approximately the same, the Sun and the Moon as seen from Earth appear to be approximately the same size: about 0.5degree of arcin angular measure.

The Moon's orbit around Earth is slightlyelliptical,as is Earth's orbit around the Sun. The apparent sizes of the Sun and Moon therefore vary.Themagnitude of an eclipseis the ratio of the apparent size of the Moon to the apparent size of the Sun during an eclipse. An eclipse that occurs when the Moon is near its closest distance to Earth (i.e.,near itsperigee) can be a total eclipse because the Moon will appear to be large enough to completely cover the Sun's bright disk orphotosphere;a total eclipse has a magnitude greater than or equal to 1.000. Conversely, an eclipse that occurs when the Moon is near its farthest distance from Earth (i.e.,near itsapogee) can be only an annular eclipse because the Moon will appear to be slightly smaller than the Sun; the magnitude of an annular eclipse is less than 1.

Because Earth's orbit around the Sun is also elliptical, Earth's distance from the Sun similarly varies throughout the year. This affects the apparent size of the Sun in the same way, but not as much as does the Moon's varying distance from Earth.When Earth approaches itsfarthest distance from the Sunin early July, a total eclipse is somewhat more likely, whereas conditions favour an annular eclipse when Earth approaches itsclosest distance to the Sunin early January.

There are three main types of solar eclipses:

Total eclipse

A total eclipse occurs on average every 18 monthswhen the dark silhouette of the Moon completely obscures the bright light of the Sun, allowing the much faintersolar coronato be visible. During an eclipse, totality occurs only along a narrow track on the surface of Earth.This narrow track is called the path of totality.

Annular eclipse

An annular eclipse, like a total eclipse, occurs when the Sun and Moon are exactly in line with Earth. During an annular eclipse, however, the apparent size of the Moon is not large enough to completely block out the Sun.Totality thus does not occur; the Sun instead appears as a very bright ring, orannulus,surrounding the dark disk of the Moon.Annular eclipses occur once every one or two years, not annually.Their name comes from theLatinroot wordanulus,meaning "ring", rather thanannus,for "year".

Partial eclipse

A partial eclipse occurs about twice a year,when the Sun and Moon are not exactly in line with Earth and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of Earth outside of the track of an annular or total eclipse. However, some eclipses can be seen only as a partial eclipse, because theumbrapasses above Earth's polar regions and never intersects Earth's surface.Partial eclipses are virtually unnoticeable in terms of the Sun's brightness, as it takes well over 90% coverage to notice any darkening at all. Even at 99%, it would be no darker thancivil twilight.

Comparison of minimum and maximum apparent sizes of the Sun and Moon (and planets). An annular eclipse can occur when the Sun has a larger apparent size than the Moon, whereas a total eclipse can occur when the Moon has a larger apparent size.

Terminology

Hybrid eclipse

A hybrid eclipse (also called annular/total eclipse) shifts between a total and annular eclipse. At certain points on the surface of Earth, it appears as a total eclipse, whereas at other points it appears as annular. Hybrid eclipses are comparatively rare.

A hybrid eclipse occurs when the magnitude of an eclipse changes during the event from less to greater than one, so the eclipse appears to be total at locations nearer the midpoint, and annular at other locations nearer the beginning and end, since the sides of Earth are slightly further away from the Moon. These eclipses are extremely narrow in their path width and relatively short in their duration at any point compared with fully total eclipses; the2023 April 20 hybrid eclipse's totality is over a minute in duration at various points along the path of totality. Like afocal point,the width and duration of totality and annularity are near zero at the points where the changes between the two occur.

Central eclipse

Each icon shows the view from the centre of its black spot, representing the Moon (not to scale)

Diamond ring effect at third contact—the end of totality—with visible prominences (August 21, 2017)

Central eclipseis often used as a generic term for a total, annular, or hybrid eclipse.This is, however, not completely correct: the definition of a central eclipse is an eclipse during which the central line of the umbra touches Earth's surface. It is possible, though extremely rare, that part of the umbra intersects with Earth (thus creating an annular or total eclipse), but not its central line. This is then called a non-central total or annular eclipse.Gammais a measure of how centrally the shadow strikes. The last (umbral yet) non-central solar eclipse wason April 29, 2014.This was an annular eclipse. The next non-central total solar eclipse will beon April 9, 2043.

Eclipse phases

The visual phases observed during a total eclipse are called:

• First contact—when the Moon's limb (edge) is exactly tangential to the Sun's limb.
• Second contact—starting withBaily's Beads(caused by light shining through valleys on the Moon's surface) and thediamond ring effect.Almost the entire disk is covered.
• Totality—the Moon obscures the entire disk of the Sun and only thesolar coronais visible.
• Third contact—when the first bright light becomes visible and the Moon's shadow is moving away from the observer. Again a diamond ring may be observed.
• Fourth contact—when the trailing edge of the Moon ceases to overlap with the solar disk and the eclipse ends.

Predictions

Geometry

Geometry of a total solar eclipse (not to scale)

The diagrams to the right show the alignment of the Sun, Moon, and Earth during a solar eclipse. The dark gray region between the Moon and Earth is theumbra,where the Sun is completely obscured by the Moon. The small area where the umbra touches Earth's surface is where a total eclipse can be seen. The larger light gray area is thepenumbra,in which a partial eclipse can be seen. An observer in theantumbra,the area of shadow beyond the umbra, will see an annular eclipse.

TheMoon's orbitaround Earth is inclined at an angle of just over 5 degrees to the plane of Earth's orbit around the Sun (theecliptic). Because of this, at the time of a new moon, the Moon will usually pass to the north or south of the Sun. A solar eclipse can occur only when a new moon occurs close to one of the points (known asnodes) where the Moon's orbit crosses the ecliptic.

As noted above, the Moon's orbit is alsoelliptical.The Moon's distance from Earth varies by up to about 5.9% from its average value. Therefore, the Moon's apparent size varies with its distance from Earth, and it is this effect that leads to the difference between total and annular eclipses. The distance of Earth from the Sun also varies during the year, but this is a smaller effect (by up to about 0.85% from its average value). On average, the Moon appears to be slightly (2.1%) smaller than the Sun as seen from Earth, so the majority (about 60%) of central eclipses are annular. It is only when the Moon is closer to Earth than average (near itsperigee) that a total eclipse occurs.

	Moon		Sun
	At perigee (nearest)	At apogee (farthest)	At perihelion (nearest)	At aphelion (farthest)
Mean radius	1737.10 km (1079.38 mi)		696000km (432000mi)
Distance	363104km (225622mi)	405696km (252088mi)	147098070km (91402500mi)	152097700km (94509100mi)
Angular diameter	33' 30 " (0.5583°)	29' 26 " (0.4905°)	32' 42 " (0.5450°)	31' 36 " (0.5267°)
Apparent size to scale
Order by decreasing apparent size	1st	4th	2nd	3rd

The Moon orbits Earth in approximately 27.3 days, relative to afixed frame of reference.This is known as thesidereal month.However, during one sidereal month, Earth has revolved part way around the Sun, making the average time between one new moon and the next longer than the sidereal month: it is approximately 29.5 days. This is known as thesynodic monthand corresponds to what is commonly called thelunar month.

The Moon crosses from south to north of the ecliptic at itsascending node,and vice versa at its descending node.However, the nodes of the Moon's orbit are gradually moving in aretrograde motion,due to the action of the Sun's gravity on the Moon's motion, and they make a complete circuit every 18.6 years. This regression means that the time between each passage of the Moon through the ascending node is slightly shorter than the sidereal month. This period is called the nodical ordraconic month.

Finally, the Moon's perigee is moving forwards or precessing in its orbit and makes a complete circuit in 8.85 years. The time between one perigee and the next is slightly longer than the sidereal month and known as theanomalistic month.

The Moon's orbit intersects with the ecliptic at the two nodes that are 180 degrees apart. Therefore, the new moon occurs close to the nodes at two periods of the year approximately six months (173.3 days) apart, known aseclipse seasons,and there will always be at least one solar eclipse during these periods. Sometimes the new moon occurs close enough to a node during two consecutive months to eclipse the Sun on both occasions in two partial eclipses. This means that, in any given year, there will always be at least two solar eclipses, and there can be as many as five.

Eclipses can occur only when the Sun is within about 15 to 18 degrees of a node, (10 to 12 degrees for central eclipses). This is referred to as an eclipse limit, and is given in ranges because the apparent sizes and speeds of the Sun and Moon vary throughout the year. In the time it takes for the Moon to return to a node (draconic month), the apparent position of the Sun has moved about 29 degrees, relative to the nodes.Since the eclipse limit creates a window of opportunity of up to 36 degrees (24 degrees for central eclipses), it is possible for partial eclipses (or rarely a partial and a central eclipse) to occur in consecutive months.

Fraction of the Sun's disc covered,f,when the same-sized discs are offset a fractiontof their diameter.

Path

From space, the Moon's shadow during thesolar eclipse of March 9, 2016appears as a dark spot moving across Earth.

During a central eclipse, the Moon's umbra (or antumbra, in the case of an annular eclipse) moves rapidly from west to east across Earth. Earth is also rotating from west to east, at about 28 km/min at the Equator, but as the Moon is moving in the same direction asEarth's rotationat about 61 km/min, the umbra almost always appears to move in a roughly west–east direction across a map of Earth at the speed of the Moon's orbital velocity minus Earth's rotational velocity.

The width of the track of a central eclipse varies according to the relative apparent diameters of the Sun and Moon. In the most favourable circumstances, when a total eclipse occurs very close to perigee, the track can be up to 267 km (166 mi) wide and the duration of totality may be over 7 minutes.Outside of the central track, a partial eclipse is seen over a much larger area of Earth. Typically, the umbra is 100–160 km wide, while the penumbral diameter is in excess of 6400 km.

Besselian elementsare used to predict whether an eclipse will be partial, annular, or total (or annular/total), and what the eclipse circumstances will be at any given location.

Calculations with Besselian elements can determine the exact shape of the umbra's shadow on Earth's surface. But at whatlongitudeson Earth's surface the shadow will fall, is a function of Earth's rotation, and on how much that rotation has slowed down over time. A number calledΔTis used in eclipse prediction to take this slowing into account. As Earth slows, ΔT increases. ΔT for dates in the future can only be roughly estimated because Earth's rotation is slowing irregularly. This means that, although it is possible to predict that there will be a total eclipse on a certain date in the far future, it is not possible to predict in the far future exactly at what longitudes that eclipse will be total. Historical records of eclipses allow estimates of past values of ΔT and so of Earth's rotation.

Duration

The following factors determine the duration of a total solar eclipse (in order of decreasing importance):

1. The Moon being almost exactly at perigee (making its angular diameter as large as possible).
2. Earth being very nearaphelion(furthest away from the Sun in its elliptical orbit, making its angular diameter nearly as small as possible).
3. The midpoint of the eclipse being very close to Earth's equator, where the rotational velocity is greatest and is closest to the speed of the lunar shadow moving over Earth's surface.
4. The vector of the eclipse path at the midpoint of the eclipse aligning with the vector of Earth's rotation (i.e. not diagonal but due east).
5. The midpoint of the eclipse being near thesubsolar point(the part of Earth closest to the Sun).

The longest eclipse that has been calculated thus far is the eclipse ofJuly 16, 2186(with a maximum duration of 7 minutes 29 seconds over northern Guyana).

Occurrence and cycles

Main article:Eclipse cycle

As Earth revolves around the Sun, approximateaxial parallelismof the Moon's orbital plane (tiltedfive degrees to Earth's orbital plane) results in the revolution of thelunar nodesrelative to Earth. This causes aneclipse seasonapproximately every six months, in which a solar eclipse can occur at thenew moonphase and alunar eclipsecan occur at thefull moonphase.

Total solar eclipse paths: 1001–2000, showing that total solar eclipses occur almost everywhere on Earth. This image was merged from 50 separate images fromNASA.

A total solar eclipse is a rare event, recurring somewhere on Earth every 18 months on average,yet is estimated to recur at any given location only every 360–410 years on average.The total eclipse lasts for only a maximum of a few minutes at any location because the Moon's umbra moves eastward at over 1700 km/h (1100 mph; 470 m/s; 1500 ft/s).Totality currently can never last more than 7 min 32 s. This value changes over the millennia and is currently decreasing. By the 8th millennium, the longest theoretically possible total eclipse will be less than 7 min 2 s.The last time an eclipse longer than 7 minutes occurred wasJune 30, 1973(7 min 3 sec).Observers aboard a Concorde supersonic aircraft were able to stretch totality for this eclipse to about 74 minutesby flying along the path of the Moon's umbra.The next total eclipse exceeding seven minutes in duration will not occur untilJune 25, 2150.The longest total solar eclipse during the11000year period from 3000 BC to at least 8000 AD will occur onJuly 16, 2186,when totality will last 7 min 29 s.For comparison, the longest total eclipse of the 20th century at 7 min 8 s occurred onJune 20, 1955,and there will be no total solar eclipses over 7 min in duration in the 21st century.

It is possible to predict other eclipses usingeclipse cycles.Thesarosis probably the best known and one of the most accurate. A saros lasts 6585.3 days (a little over 18 years), which means that, after this period, a practically identical eclipse will occur. The most notable difference will be a westward shift of about 120° in longitude (due to the 0.3 days) and a little in latitude (north-south for odd-numbered cycles, the reverse for even-numbered ones). A saros series always starts with a partial eclipse near one of Earth's polar regions, then shifts over the globe through a series of annular or total eclipses, and ends with a partial eclipse at the opposite polar region. A saros series lasts 1226 to 1550 years and 69 to 87 eclipses, with about 40 to 60 of them being central.

Frequency per year

Between two and five solar eclipses occur every year, with at least one pereclipse season.Since theGregorian calendarwas instituted in 1582, years that have had five solar eclipses were 1693, 1758, 1805, 1823, 1870, and 1935. The next occurrence will be 2206.On average, there are about 240 solar eclipses each century.

The five solar eclipses of 1935

January 5	February 3	June 30	July 30	December 25
Partial (south)	Partial (north)	Partial (north)	Partial (south)	Annular (south)
Saros 111	Saros 149	Saros 116	Saros 154	Saros 121

Final totality

Total solar eclipses are seen on Earth because of a fortuitous combination of circumstances. Even on Earth, the diversity of eclipses familiar to people today is a temporary (on a geological time scale) phenomenon. Hundreds of millions of years in the past, the Moon was closer to Earth and therefore apparently larger, so every solar eclipse was total or partial, and there were no annular eclipses. Due totidal acceleration,the orbit of the Moon around Earth becomes approximately 3.8 cm more distant each year. Millions of years in the future, the Moon will be too far away to fully occlude the Sun, and no total eclipses will occur. In the same timeframe, the Sun may become brighter, making it appear larger in size.Estimates of the time when the Moon will be unable to occlude the entire Sun when viewed from Earth range between 650 millionand 1.4 billion years in the future.

Viewing

2017 total solar eclipseviewed in real time with audience reactions

Looking directly at thephotosphereof the Sun (the bright disk of the Sun itself), even for just a few seconds, can cause permanentdamageto theretinaof the eye, because of the intense visible and invisible radiation that the photosphere emits. This damage can result in impairment of vision, up to and includingblindness.The retina has no sensitivity to pain, and the effects of retinal damage may not appear for hours, so there is no warning that injury is occurring.

Under normal conditions, the Sun is so bright that it is difficult to stare at it directly. However, during an eclipse, with so much of the Sun covered, it is easier and more tempting to stare at it. Looking at the Sun during an eclipse is as dangerous as looking at it outside an eclipse, except during the brief period of totality, when the Sun's disk is completely covered (totality occurs only during a total eclipse and only very briefly; it does not occur during a partial or annular eclipse). Viewing the Sun's disk through any kind of optical aid (binoculars, a telescope, or even an optical camera viewfinder) is extremely hazardous and can cause irreversible eye damage within a fraction of a second.

Partial and annular eclipses

Eclipse glassesfilter out eye damaging radiation, allowing direct viewing of the Sun during all partial eclipse phases; they are not used during totality, when the Sun is completely eclipsed

Pinhole projection method of observing partial solar eclipse. Insert (upper left): partially eclipsed Sun photographed with a white solar filter. Main image: projections of the partially eclipsed Sun (bottom right)

Viewing the Sun during partial and annular eclipses (and during total eclipses outside the brief period of totality) requires special eye protection, or indirect viewing methods if eye damage is to be avoided. The Sun's disk can be viewed using appropriate filtration to block the harmful part of the Sun's radiation. Sunglasses do not make viewing the Sun safe. Only properly designed and certified solar filters should be used for direct viewing of the Sun's disk.Especially, self-made filters using common objects such as afloppy diskremoved from its case, aCompact Disc,a black colour slide film, smoked glass, etc. must be avoided.

The safest way to view the Sun's disk is by indirect projection.This can be done by projecting an image of the disk onto a white piece of paper or card using a pair of binoculars (with one of the lenses covered), a telescope, or another piece of cardboard with a small hole in it (about 1 mm diameter), often called apinhole camera.The projected image of the Sun can then be safely viewed; this technique can be used to observesunspots,as well as eclipses. Care must be taken, however, to ensure that no one looks through the projector (telescope, pinhole, etc.) directly.A kitchencolanderwith small holes can also be used to project multiple images of the partially eclipsed Sun onto the ground or a viewing screen. Viewing the Sun's disk on a video display screen (provided by avideo cameraordigital camera) is safe, although the camera itself may be damaged by direct exposure to the Sun. The optical viewfinders provided with some video and digital cameras are not safe. Securely mounting #14 welder's glass in front of the lens and viewfinder protects the equipment and makes viewing possible.Professional workmanship is essential because of the dire consequences any gaps or detaching mountings will have. In the partial eclipse path, one will not be able to see the corona or nearly complete darkening of the sky. However, depending on how much of the Sun's disk is obscured, some darkening may be noticeable. If three-quarters or more of the Sun is obscured, then an effect can be observed by which the daylight appears to be dim, as if the sky were overcast, yet objects still cast sharp shadows.

Totality

Solar eclipse of August 21, 2017

Baily's beads,sunlight visible through lunar valleys

Composite image withcorona,prominences,and diamond ring effect

When the shrinking visible part of the photosphere becomes very small,Baily's beadswill occur. These are caused by the sunlight still being able to reach Earth through lunar valleys. Totality then begins with thediamond ring effect,the last bright flash of sunlight.

It is safe to observe the total phase of a solar eclipse directly only when the Sun's photosphere is completely covered by the Moon, and not before or after totality.During this period, the Sun is too dim to be seen through filters. The Sun's faintcoronawill be visible, and thechromosphere,solar prominences,coronal streamersand possibly even asolar flaremay be seen. At the end of totality, the same effects will occur in reverse order, and on the opposite side of the Moon.

Eclipse chasing

Main article:Eclipse chasing

A dedicated group of eclipse chasers have pursued the observation of solar eclipses when they occur around Earth.A person who chases eclipses is known as an umbraphile, meaning shadow lover.Umbraphiles travel for eclipses and use various tools to help view the sun includingsolar viewing glasses,also known as eclipse glasses, as well as telescopes.

Photography

The progression of asolar eclipse on August 1, 2008inNovosibirsk,Russia.All times UTC (local time was UTC+7). The time span between shots is three minutes.

The first known photograph of a solar eclipse was taken on July 28, 1851, byJohann Julius Friedrich Berkowski,using thedaguerreotypeprocess.

Photographing an eclipse is possible with fairly common camera equipment. In order for the disk of the Sun/Moon to be easily visible, a fairly high magnificationlong focus lensis needed (at least 200 mm for a 35 mm camera), and for the disk to fill most of the frame, a longer lens is needed (over 500 mm). As with viewing the Sun directly, looking at it through the optical viewfinder of a camera can produce damage to the retina, so care is recommended.Solar filters are required for digital photography even if an optical viewfinder is not used. Using a camera's live view feature or an electronic viewfinder is safe for the human eye, but the Sun's rays could potentially irreparably damage digital image sensors unless the lens is covered by a properly designed solar filter.

Pinholes in shadows during no eclipse (1 & 4), a partial eclipse (2 & 5) and an annular eclipse (3 & 6)

Pinhole shadows during the Solar eclipse of April 8, 2024, as seen from Winder, Georgia.

Historical eclipses

Further information:Eclipses in mythology and cultureandLists of solar eclipses

Astronomers Studying an Eclipse,Antoine Caron,1571

Historical eclipses are a very valuable resource for historians, in that they allow a few historical events to be dated precisely, from which other dates and ancient calendars may be deduced.The oldest recorded solar eclipse was recorded on a clay tablet found atUgarit,in modernSyria,with two plausible dates usually cited: 3 May 1375 BC or 5 March 1223 BC, the latter being favored by most recent authors on the topic.Asolar eclipse of June 15, 763 BCmentioned in anAssyriantext is important for thechronology of the ancient Near East.There have been other claims to date earlier eclipses. The legendary Chinese kingZhong Kangsupposedly beheaded two astronomers, Hsi and Ho, who failed to predict an eclipse 4000 years ago.Perhaps the earliest still-unproven claim is that of archaeologist Bruce Masse, who putatively links an eclipse that occurred on May 10, 2807, BC with a possiblemeteor impactin theIndian Oceanon the basis of several ancientflood mythsthat mention a total solar eclipse.

Records of the solar eclipses of 993 and 1004 as well as the lunar eclipses of 1001 and 1002 byIbn Yunusof Cairo (c. 1005).

Eclipses have been interpreted asomens,or portents.The ancient Greek historianHerodotuswrote thatThales of Miletuspredictedan eclipse that occurred during a battlebetween theMedesand theLydians.Both sides put down their weapons and declared peace as a result of the eclipse.The exact eclipse involved remains uncertain, although the issue has been studied by hundreds of ancient and modern authorities. One likely candidate took place on May 28, 585 BC, probably near theHalysriver inAsia Minor.An eclipse recorded by Herodotus beforeXerxesdeparted for his expedition againstGreece,which is traditionally dated to 480 BC, was matched byJohn Russell Hindto an annular eclipse of the Sun atSardison February 17, 478 BC.Alternatively, a partial eclipse was visible from Persia on October 2, 480 BC.Herodotus also reports a solar eclipse atSpartaduring theSecond Persian invasion of Greece.The date of the eclipse (August 1, 477 BC) does not match exactly the conventional dates for the invasion accepted by historians.

In ancient China, where solar eclipses were known as an "eating of the Sun" (rìshíNhật thực), the earliest records of eclipses date to around 720 BC.The 4th century BC astronomerShi Shendescribed the prediction of eclipses by using the relative positions of the Moon and Sun.

Attempts have been made to establish the exact date ofGood Fridayby assuming that thedarkness described at Jesus's crucifixionwas a solar eclipse. This research has not yielded conclusive results,and Good Friday is recorded as being atPassover,which is held at the time of a full moon. Further, the darkness lasted from the sixth hour to the ninth, or three hours, which is much, much longer than the eight-minute upper limit for any solar eclipse's totality. Contemporary chronicles wrote about an eclipse at the beginning of May664that coincided with the beginning of theplague of 664in the British isles.In the Western hemisphere, there are few reliable records of eclipses before AD 800, until the advent of Arab and monastic observations in the early medieval period.

Asolar eclipse took place on January 27, 632 over ArabiaduringMuhammad's lifetime. Muhammad denied the eclipse had anything to do with his son dying earlier that day, saying "The sun and the moon do not eclipse because of the death of someone from the people but they are two signs amongst the signs of God."The Cairo astronomerIbn Yunuswrote that the calculation of eclipses was one of the many things that connect astronomy with theIslamic law,because it allowed knowing whena special prayercan be made.The first recorded observation of the corona was made inConstantinoplein AD 968.

Erhard Weigel,predicted course of Moon shadow on 12 August 1654 (O.S.2 August)

The first known telescopic observation of a total solar eclipse was made in France in 1706.Nine years later, English astronomerEdmund Halleyaccurately predicted and observed thesolar eclipse of May 3, 1715.By the mid-19th century, scientific understanding of the Sun was improving through observations of the Sun's corona during solar eclipses. The corona was identified as part of the Sun's atmosphere in1842,and the first photograph (ordaguerreotype) of a total eclipse was taken of thesolar eclipse of July 28, 1851.Spectroscopeobservations were made of thesolar eclipse of August 18, 1868,which helped to determine the chemical composition of the Sun.

John Fiskesummed up myths about the solar eclipse like this in his 1872 bookMyth and Myth-Makers,

the myth of Hercules and Cacus, the fundamental idea is the victory of the solar god over the robber who steals the light. Now whether the robber carries off the light in the evening when Indra has gone to sleep, or boldly rears his black form against the sky during the daytime, causing darkness to spread over the earth, would make little difference to the framers of the myth. To a chicken a solar eclipse is the same thing as nightfall, and he goes to roost accordingly. Why, then, should the primitive thinker have made a distinction between the darkening of the sky caused by black clouds and that caused by the rotation of the earth? He had no more conception of the scientific explanation of these phenomena than the chicken has of the scientific explanation of an eclipse. For him it was enough to know that the solar radiance was stolen, in the one case as in the other, and to suspect that the same demon was to blame for both robberies.

Particular observations, phenomena and impact

Simulated solar eclipse with a still illuminated and refracting horizon, as well as thecoronal streamers,

A total solar eclipse provides a rare opportunity to observe thecorona(the outer layer of the Sun's atmosphere). Normally this is not visible because thephotosphereis much brighter than the corona. According to the point reached in thesolar cycle,the corona may appear small and symmetric, or large and fuzzy. It is very hard to predict this in advance.

Phenomena associated with eclipses includeshadow bands(also known asflying shadows), which are similar to shadows on the bottom of a swimming pool. They occur only just prior to and after totality, when a narrow solar crescent acts as ananisotropiclight source.As the light filters through leaves of trees during a partial eclipse, the overlapping leaves create natural pinholes, displaying mini eclipses on the ground.

1919 observations

See also:Tests of general relativity § Deflection of light by the Sun

Eddington's original photograph of the 1919 eclipse, which provided evidence forEinstein's theory ofgeneral relativity.

The observation of a totalsolar eclipse of May 29, 1919,helped to confirmEinstein's theory ofgeneral relativity.By comparing the apparent distance between stars in the constellationTaurus,with and without the Sun between them,Arthur Eddingtonstated that thetheoretical predictionsaboutgravitational lenseswere confirmed.The observation with the Sun between the stars was possible only during totality since the stars are then visible. Though Eddington's observations were near the experimental limits of accuracy at the time, work in the later half of the 20th century confirmed his results.

Gravity anomalies

There is a long history of observations of gravity-related phenomena during solar eclipses, especially during the period of totality. In 1954, and again in 1959,Maurice Allaisreported observations of strange and unexplained movement during solar eclipses.The reality of this phenomenon, named theAllais effect,has remained controversial. Similarly, in 1970,SaxlandAllenobserved the sudden change in motion of a torsion pendulum; this phenomenon is called the Saxl effect.

Observation during the 1997 solar eclipse by Wanget al.suggested a possiblegravitational shieldingeffect,which generated debate. In 2002, Wang and a collaborator published detailed data analysis, which suggested that the phenomenon still remains unexplained.

Eclipses and transits

In principle, the simultaneous occurrence of a solar eclipse and atransitof a planet is possible. But these events are extremely rare because of their short durations. The next anticipated simultaneous occurrence of a solar eclipse and atransit of Mercurywill be on July 5, 6757, and a solar eclipse and atransit of Venusis expected on April 5,15232.

More common, but still infrequent, is aconjunctionof a planet (especially, but not only, Mercury or Venus) at the time of a total solar eclipse, in which event the planet will be visible very near the eclipsed Sun, when without the eclipse it would have been lost in the Sun's glare. At one time, some scientists hypothesized that there may be a planet (often given the nameVulcan) even closer to the Sun than Mercury; the only way to confirm its existence would have been to observe it in transit or during a total solar eclipse. No such planet was ever found, andgeneral relativityhas since explained the observations that led astronomers to suggest that Vulcan might exist.

Artificial satellites

The Moon's shadow overTurkeyandCyprus,seen from theISSduring a2006 total solar eclipse.

A composite image showing the ISS transit of the Sun while the 2017 solar eclipse was in progress

Artificial satellites can also pass in front of the Sun as seen from Earth, but none is large enough to cause an eclipse. At the altitude of theInternational Space Station,for example, an object would need to be about 3.35 km (2.08 mi) across to blot the Sun out entirely. These transits are difficult to watch because the zone of visibility is very small. The satellite passes over the face of the Sun in about a second, typically. As with a transit of a planet, it will not get dark.

Observations of eclipses from spacecraft or artificial satellites orbiting above Earth's atmosphere are not subject to weather conditions. The crew ofGemini 12observed a total solar eclipse from space in 1966.The partial phase of the1999 total eclipsewas visible fromMir.

Impact

Thesolar eclipse of March 20, 2015,was the first occurrence of an eclipse estimated to potentially have a significant impact on the power system, with the electricity sector taking measures to mitigate any impact. Thecontinental EuropeandGreat Britainsynchronous areas were estimated to have about 90gigawattsofsolar powerand it was estimated that production would temporarily decrease by up to 34 GW compared to a clear sky day.

Eclipses may cause the temperature to decrease by 3 °C (5 °F), withwind powerpotentially decreasing as winds are reduced by 0.7 meters (2.3 ft) per second.

In addition to the drop in light level and air temperature, animals change their behavior during totality. For example, birds and squirrels return to their nests and crickets chirp.

Recent and forthcoming solar eclipses

Main article:List of solar eclipses in the 21st century

Further information:Lists of solar eclipses

Eclipse path for total and hybrid eclipses from 2021 to 2040

Eclipses occur only in theeclipse season,when the Sun is close to either the ascending or descendingnode of the Moon.Each eclipse is separated by one, five or sixlunations(synodic months), and the midpoint of each season is separated by 173.3 days, which is the mean time for the Sun to travel from one node to the next. The period is a little less than half a calendar year because the lunar nodes slowly regress. Because 223 synodic months is roughly equal to 239anomalistic monthsand 242draconic months,eclipses with similar geometry recur 223 synodic months (about 6,585.3 days) apart. This period (18 years 11.3 days) is asaros.Because 223 synodic months is not identical to 239 anomalistic months or 242 draconic months, saros cycles do not endlessly repeat. Each cycle begins with the Moon's shadow crossing Earth near the north or south pole, and subsequent events progress toward the other pole until the Moon's shadow misses Earth and the series ends.Saros cycles are numbered; currently, cycles 117 to 156 are active.

1997–2000

This eclipse is a member of asemester series.An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Solar eclipseseries sets from 1997 to 2000

Descending node				Ascending node
Saros	Map	Gamma		Saros	Map	Gamma
120 Chita, Russia	1997 March 09 Total	0.91830		125	1997 September 02 Partial (south)	−1.03521
130 Total eclipse nearGuadeloupe	1998 February 26 Total	0.23909		135	1998 August 22 Annular	−0.26441
140	1999 February 16 Annular	−0.47260		145 Totality fromFrance	1999 August 11 Total	0.50623
150	2000 February 05 Partial (south)	−1.22325		155	2000 July 31 Partial (north)	1.21664

Partial solar eclipses onJuly 1, 2000andDecember 25, 2000occur in the next lunar year eclipse set.

2000–2003

This eclipse is a member of asemester series.An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Partial solar eclipses onFebruary 5, 2000andJuly 31, 2000occur in the previous lunar year set.

Solar eclipseseries sets from 2000 to 2003

Ascending node				Descending node
Saros	Map	Gamma		Saros	Map	Gamma
117	2000 July 01 Partial (south)	−1.28214		122	2000 December 25 Partial (north)	1.13669
127 Totality fromLusaka, Zambia	2001 June 21 Total	−0.57013		132 Partial fromMinneapolis, MN	2001 December 14 Annular	0.40885
137 Partial fromLos Angeles, CA	2002 June 10 Annular	0.19933		142 Totality fromWoomera	2002 December 04 Total	−0.30204
147 Culloden, Scotland	2003 May 31 Annular	0.99598		152	2003 November 23 Total	−0.96381

2004–2007

This eclipse is a member of asemester series.An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Solar eclipseseries sets from 2004 to 2007

Ascending node				Descending node
Saros	Map	Gamma		Saros	Map	Gamma
119	2004 April 19 Partial (south)	−1.13345		124	2004 October 14 Partial (north)	1.03481
129 Partial fromNaiguatá	2005 April 08 Hybrid	−0.34733		134 Annular fromMadrid,Spain	2005 October 03 Annular	0.33058
139 Total fromSide, Turkey	2006 March 29 Total	0.38433		144 Partial fromSão Paulo,Brazil	2006 September 22 Annular	−0.40624
149 FromJaipur,India	2007 March 19 Partial (north)	1.07277		154 FromCórdoba, Argentina	2007 September 11 Partial (south)	−1.12552

2008–2011

This eclipse is a member of asemester series.An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Solar eclipseseries sets from 2008 to 2011

Ascending node				Descending node
Saros	Map	Gamma		Saros	Map	Gamma
121 Partial fromChristchurch,NZ	2008 February 07 Annular	−0.95701		126 Novosibirsk, Russia	2008 August 01 Total	0.83070
131 Palangka Raya,Indonesia	2009 January 26 Annular	−0.28197		136 Kurigram,Bangladesh	2009 July 22 Total	0.06977
141 Bangui, Central African Republic	2010 January 15 Annular	0.40016		146 Hao, French Polynesia	2010 July 11 Total	−0.67877
151 Partial fromVienna, Austria	2011 January 04 Partial (north)	1.06265		156	2011 July 01 Partial (south)	−1.49171

Partial solar eclipses onJune 1, 2011,andNovember 25, 2011,occur on the next lunar year eclipse set.

2011–2014

This eclipse is a member of the 2011–2014 solar eclipse semester series. An eclipse in asemester seriesof solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Solar eclipseseries sets from 2011 to 2014

Descending node				Ascending node
Saros	Map	Gamma		Saros	Map	Gamma
118 Partial fromTromsø,Norway	2011 June 01 Partial (north)	1.21300		123 Hinode XRT footage	2011 November 25 Partial (south)	−1.05359
128 Middlegate, Nevada	2012 May 20 Annular	0.48279		133 Cairns,Australia	2012 November 13 Total	−0.37189
138 Churchills Head,Australia	2013 May 10 Annular	−0.26937		143 Partial fromLibreville, Gabon	2013 November 03 Hybrid	0.32715
148 Partial fromAdelaide,Australia	2014 April 29 Annular (non-central)	−0.99996		153 Partial fromMinneapolis	2014 October 23 Partial (north)	1.09078

2015–2018

This eclipse is a member of asemester series.An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Solar eclipseseries sets from 2015 to 2018

Descending node				Ascending node
Saros	Map	Gamma		Saros	Map	Gamma
120 Longyearbyen,Svalbard	2015 March 20 Total	0.94536		125 Solar Dynamics Observatory	2015 September 13 Partial (south)	−1.10039
130 Balikpapan,Indonesia	2016 March 9 Total	0.26092		135 L'Étang-Salé,Réunion	2016 September 1 Annular	−0.33301
140 Partial fromBuenos Aires	2017 February 26 Annular	−0.45780		145 Casper, Wyoming	2017 August 21 Total	0.43671
150 Partial fromOlivos, Buenos Aires	2018 February 15 Partial (south)	−1.21163		155 Partial fromHuittinen,Finland	2018 August 11 Partial (north)	1.14758

Partial solar eclipses onJuly 13, 2018,andJanuary 6, 2019,occur during the next semester series.

2018–2021

This eclipse is a member of asemester series.An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Note: Partial solar eclipses onFebruary 15, 2018,andAugust 11, 2018,occurred during the previoussemester series.

Solar eclipseseries sets from 2018 to 2021

Ascending node				Descending node
Saros	Map	Gamma		Saros	Map	Gamma
117 Partial fromMelbourne,Australia	2018 July 13 Partial	−1.35423		122 Partial fromNakhodka,Russia	2019 January 6 Partial	1.14174
127 La Serena, Chile	2019 July 2 Total	−0.64656		132 Jaffna, Sri Lanka	2019 December 26 Annular	0.41351
137 Beigang, Yunlin,Taiwan	2020 June 21 Annular	0.12090		142 Gorbea, Chile	2020 December 14 Total	−0.29394
147 Partial fromHalifax, Canada	2021 June 10 Annular	0.91516		152 From HMS Protector offSouth Georgia	2021 December 4 Total	−0.95261

2022–2025

This eclipse is a member of asemester series.An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Solar eclipseseries sets from 2022 to 2025
Ascending node				Descending node
Saros	Map	Gamma		Saros	Map	Gamma
119 Partial fromCTIO,Chile	2022 April 30 Partial	−1.19008		124 Partial fromSaratov, Russia	2022 October 25 Partial	1.07014
129 Total from East Timor	2023 April 20 Hybrid	−0.39515		134 Annular from Campeche,Mexico	2023 October 14 Annular	0.37534
139 Total from Indianapolis,USA	2024 April 8 Total	0.34314		144	2024 October 2 Annular	−0.35087
149	2025 March 29 Partial	1.04053		154	2025 September 21 Partial	−1.06509

2026–2029

This eclipse is a member of asemester series.An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodesof the Moon's orbit.

Solar eclipseseries sets from 2026 to 2029

Ascending node				Descending node
Saros	Map	Gamma		Saros	Map	Gamma
121	2026 February 17 Annular	−0.97427		126	2026 August 12 Total	0.89774
131	2027 February 6 Annular	−0.29515		136	2027 August 2 Total	0.14209
141	2028 January 26 Annular	0.39014		146	2028 July 22 Total	−0.60557
151	2029 January 14 Partial	1.05532		156	2029 July 11 Partial	−1.41908

Partial solar eclipses onJune 12, 2029,andDecember 5, 2029,occur in the next lunar year eclipse set.

See also

• Lists of solar eclipses
• List of films featuring eclipses
• Apollo–Soyuz:First joint U.S.–Soviet space flight. Mission included an arranged eclipse of the Sun by the Apollo module to allow instruments on the Soyuz to take photographs of the solar corona.
• Eclipse chasing:Travel to eclipse locations for study and enjoyment
• Occultation:Generic term for occlusion of an object by another object that passes between it and the observer, thus revealing (for example) the presence of an exoplanet orbiting a distant star by eclipsing it as seen from Earth
• Eclipses in history and culture:treatment of solar and lunar eclipses by historical and contemporary society and religion
• Solar eclipses in fiction
• Solar eclipses on the Moon:Eclipse of the Sun by planet Earth, as seen from the Moon
  • Lunar eclipse:Solar eclipse of the Moon, as seen from Earth; the shadow cast on the Moon by that eclipse
• Transit of Venus:Passage of the planet Venus between the Sun and Earth, as seen from Earth. Technically a partial eclipse.
• Transit of Deimos from Mars:Passage of the Martian moon Deimos between the Sun and Mars, as seen from Mars
• Transit of Phobos from Mars:Passage of the Martian moon Phobos between the Sun and Mars, as seen from Mars

Bibliography

• Mucke, Hermann;Meeus, Jean(1992).Canon of Solar Eclipses −2003 to +2526(2 ed.). Vienna: Astronomisches Büro.
• Harrington, Philip S. (1997).Eclipse! The What, Where, When, Why and How Guide to Watching Solar and Lunar Eclipses.New York: John Wiley and Sons.ISBN0-471-12795-7.
• Steel, Duncan(1999).Eclipse: The celestial phenomenon which has changed the course of history.London: Headline.ISBN0-7472-7385-5.
• Mobberley, Martin (2007).Total Solar Eclipses and How to Observe Them.Astronomers' Observing Guides. New York: Springer.ISBN978-0-387-69827-4.
• Espenak, Fred(2015).Thousand Year Canon of Solar Eclipses 1501 to 2500.Portal AZ: Astropixels Publishing.ISBN978-1-941983-02-7.
• Espenak, Fred (2016).21st Century Canon of Solar Eclipses.Portal AZ: Astropixels Publishing.ISBN978-1-941983-12-6.
• Fotheringham, John Knight(1921).Historical eclipses:being the Halley lecture delivered 17 May 1921.Oxford: Clarendon Press.

External links

• NASA Eclipse Web Site, with information on future eclipses and eye safety information
• NASA Eclipse Web Site (older version)
• Eclipsewise,Fred Espenak's new eclipse site
• Andrew Lowe's Eclipse Page,with maps and circumstances for 5000 years of solar eclipses
• A Guide to Eclipse Activities for Educators,Explaining eclipses in educational settings
• Detailed eclipse explanations and predictions,Hermit Eclipse
• Eclipse Photography,Prof. Miroslav Druckmüller
• Animated maps of August 21, 2017 solar eclipses,Larry Koehn
• Five Millennium (−1999 to +3000) Canon of Solar Eclipses Database,Xavier M. Jubier
• Animated explanation of the mechanics of a solar eclipseArchived2013-05-25 at theWayback Machine,University of South Wales
• Eclipse Image GalleryArchived2016-10-15 at theWayback Machine,The World at Night
• Ring of Fire Eclipse: 2012,Photos
• "Sun, Eclipses of the".Collier's New Encyclopedia.1921.
• Centered and aligned video recording of Total Solar Eclipse 20th March 2015onYouTube
• Solar eclipse photographs taken from the Lick Observatory from the Lick Observatory Records Digital Archive, UC Santa Cruz Library’s Digital CollectionsArchived2020-06-05 at theWayback Machine
• Video with Total Solar Eclipse March 09 2016 (from the beginning to the total phase)onYouTube
• Total Solar Eclipse Shadow on Earth March 09 2016CIMSSSatelite
• List of all solar eclipses
• National Geographic Solar Eclipse 101 videoArchived2018-08-04 at theWayback Machine
• Wikiversity has a solar eclipse lab that students can do on any sunny day.