An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three celestial objects is known as a syzygy. An eclipse is the result of either an occultation or a transit. A "deep eclipse" is when a small astronomical object is behind a bigger one.
A lunar eclipse is an astronomical event that occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. Such an alignment occurs during an eclipse season, approximately every six months, during the full moon phase, when the Moon's orbital plane is closest to the plane of the Earth's orbit.
The Moon is Earth's only natural satellite. It orbits at an average distance of 384,400 km (238,900 mi), about 30 times the diameter of Earth. Over time Earth's gravity has caused tidal locking, causing the same side of the Moon to always face Earth. Because of this, the lunar day and the lunar month are the same length, at 29.5 Earth days. The Moon's gravitational pull – and to a lesser extent, the Sun's – are the main drivers of Earth's tides.
A lunar phase or Moon phase is the apparent shape of the Moon's directly sunlit portion as viewed from the Earth. In common usage, the four major phases are the new moon, the first quarter, the full moon and the last quarter; the four minor phases are waxing crescent, waxing gibbous, waning gibbous, and waning crescent. A lunar month is the time between successive recurrences of the same phase: due to the eccentricity of the Moon's orbit, this duration is not perfectly constant but averages about 29.5 days.
The saros is a period of exactly 223 synodic months, approximately 6585.321 days, or 18 years, 10, 11, or 12 days, and 8 hours, that can be used to predict eclipses of the Sun and Moon. One saros period after an eclipse, the Sun, Earth, and Moon return to approximately the same relative geometry, a near straight line, and a nearly identical eclipse will occur, in what is referred to as an eclipse cycle. A sar is one half of a saros.
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 when foreground objects obscure distant objects dynamically, as the scene changes over time.
In astronomy, an extraterrestrial sky is a view of outer space from the surface of an astronomical body other than Earth.
The Baily's beads, diamond ring or more rarely double diamond ring effects, are features of total and annular solar eclipses. Although caused by the same phenomenon, they are distinct events during these types of solar eclipses. As the Moon covers the Sun during a solar eclipse, the rugged topography of the lunar limb allows beads of sunlight to shine through in some places while not in others. They are named for Francis Baily, who explained the effects in 1836. The diamond ring effects are seen when only one or two beads are left, appearing as shining "diamonds" set in a bright ring around the lunar silhouette.
The selenographic coordinate system is used to refer to locations on the surface of Earth's moon. Any position on the lunar surface can be referenced by specifying two numerical values, which are comparable to the latitude and longitude of Earth. The longitude gives the position east or west of the Moon's prime meridian, which is the line passing from the lunar north pole through the point on the lunar surface directly facing Earth to the lunar south pole. This can be thought of as the midpoint of the visible Moon as seen from the Earth. The latitude gives the position north or south of the lunar equator. Both of these coordinates are given in degrees.
The far side of the Moon is the lunar hemisphere that always faces away from Earth, opposite to the near side, because of synchronous rotation in the Moon's orbit. Compared to the near side, the far side's terrain is rugged, with a multitude of impact craters and relatively few flat and dark lunar maria ("seas"), giving it an appearance closer to other barren places in the Solar System such as Mercury and Callisto. It has one of the largest craters in the Solar System, the South Pole–Aitken basin. The hemisphere has sometimes been called the "dark side of the Moon", where "dark" means "unknown" instead of "lacking sunlight" – each location on the Moon experiences two weeks of sunlight while the opposite location experiences night.
A lunar standstill or lunistice is when the Moon reaches its furthest north or furthest south point during the course of a month. The declination at lunar standstill varies in a cycle 18.6 years long between 18.134° and 28.725°, due to lunar precession. These extremes are called the minor and major lunar standstills.
A solar eclipse occurs when the Moon passes between Earth and the Sun, 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 the eclipse season in its new moon phase, when the Moon's orbital plane is closest to the plane of Earth's orbit. In a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses, only part of the Sun is obscured. Unlike a lunar eclipse, which may be viewed from anywhere on the night side 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.
A total lunar eclipse will take place on May 26, 2040. The northern limb of the Moon will pass through the center of the Earth's shadow. This is the second central lunar eclipse of Saros series 131. This lunar event will occur near perigee, as a result, it will be referred to as a "super flower blood moon" or "super blood moon", though not quite as close to Earth as the eclipse of May 26, 2021.
A total lunar eclipse occurred on Tuesday, 8 November 2022. The southern limb of the Moon passed through the center of the Earth's shadow. It surpassed the previous eclipse as the longest total lunar eclipse visible from nearly all of North America since 17 August 1989, and until 26 June 2029. Occurring only 5.8 days before apogee, the Moon's apparent diameter was smaller. The next total lunar eclipse will take place on 14 March 2025. A lunar occultation of Uranus happened during the eclipse. It was the first total lunar eclipse on Election Day in US history. This event was referred in media coverage as a "beaver blood moon".
A total lunar eclipse occurred on 15–16 May 2022, the first of two total lunar eclipses in 2022. The event occurred near lunar perigee; as a result, this event was referred to some in media coverage as a "super flower blood moon" and elsewhere as a "super blood moon", a supermoon that coincides with a total lunar eclipse. This was the longest total lunar eclipse visible from nearly all of North America since August 17, 1989 until the next eclipse on November 8.
A total lunar eclipse occurred on 31 January 2018. The Moon was near its perigee on 30 January and as such may be described as a "supermoon", when the Moon's distance from the Earth is less than 360,000 km. The previous supermoon lunar eclipse was in September 2015.
A penumbral lunar eclipse took place on Tuesday, September 27, 1977, the second of two lunar eclipses in 1977. At maximum eclipse, 90.076% of the Moon's disc was partially shaded by the Earth, which caused a slight shadow gradient across its disc; this subtle effect may have been visible to careful observers. No part of the Moon was in complete shadow. The eclipse lasted 4 hours, 17 minutes and 35.5 seconds overall. Occurring 6.2 days before apogee, the Moon's apparent diameter was 2.2% smaller than average.
A penumbral lunar eclipse took place at the Moon's ascending of the orbit on Sunday, June 5, 1955, with a penumbral eclipse magnitude of 0.62181 (62.181%). A penumbral lunar eclipse takes place when the Moon moves through the faint, outer part of Earth's shadow, the penumbra. This type of eclipse is not as dramatic as other types of lunar eclipses and is often mistaken for a regular Full Moon. The Moon shines because its surface reflects the Sun's rays. A lunar eclipse happens when the Earth comes between the Sun and the Moon and blocks some or all of the Sun's light from reaching the Moon. A penumbral lunar eclipse occurs when the Sun, Earth, and the Moon are imperfectly aligned. When this happens, the Earth blocks some of the Sun's light from directly reaching the Moon's surface and covers all or part of the Moon with the outer part of its shadow, also known as the penumbra. Since the penumbra is much fainter than the dark core of the Earth's shadow, the umbra, a penumbral eclipse of the Moon is often difficult to tell apart from a normal Full Moon. Occurring only 0.5 days after apogee, the moon's apparent diameter was 6.5% smaller than average.
A total lunar eclipse took place at the Moon's descending node of the orbit on Tuesday, May 24, 1910 with an umbral eclipse magnitude of 1.09503. A total lunar eclipse takes place when the Earth comes between the Sun and the Moon and its shadow covers the Moon. Eclipse watchers can see the Moon turn red when the eclipse reaches totality. Total eclipses of the Moon happen at Full Moon when the Sun, Earth, and Moon are aligned to form a line. The astronomical term for this type of alignment is syzygy, which comes from the Greek word for being paired together. The Moon does not have its own light but shines because its surface reflects the Sun's rays. During a total lunar eclipse, the Earth comes between the Sun and the Moon and blocks any direct sunlight from reaching the Moon. The Sun casts the Earth's shadow on the Moon's surface. A shallow total eclipse saw the Moon in relative darkness for 49 minutes and 29.5 seconds. The Moon was 9.503% of its diameter into the Earth's umbral shadow, and should have been significantly darkened. The partial eclipse lasted for 3 hours, 35 minutes and 22.9 seconds in total.
Solar eclipses on the Moon are caused when the planet Earth passes in front of the Sun and blocks its light. Viewers on Earth experience a lunar eclipse during a solar eclipse on the Moon.
