Lunar Eclipse Essay Sample

The June 2011 sum occultation
A lunar occultation occurs when the Moon base on ballss straight behind the Earth into its umbra ( shadow ) . This can happen merely when the Sun. Earth. and Moon are aligned ( in “syzygy” ) precisely. or really closely so. with the Earth in the center. Hence. a lunar occultation can merely happen the dark of a full Moon. The type and length of an occultation depend upon the Moon’s location relation to its orbital nodes. Unlike a solar occultation. which can merely be viewed from a certain comparatively little country of the universe. a lunar occultation may be viewed from anyplace on the dark side of the Earth. A lunar occultation lasts for a few hours. whereas a entire solar occultation stopping points for merely a few proceedingss at any given topographic point. due to the smaller size of the moon’s shadow. Besides unlike solar occultations. lunar occultations are safe to see without any oculus protection or particular safeguards. as they are no brighter ( so dimmer ) than the full Moon itself.

Types of lunar occultation

Conventional diagram of the shadow dramatis personae by the Earth. Within the cardinal umbra shadow. the Moon is wholly shielded from direct light by the Sun. In contrast. within the penumbrashadow. merely a part of sunshine is blocked.

As seen by an perceiver on Earth on the fanciful celestial domain. the Moon crosses the ecliptic every orbit at places called nodes twice every month. When the full Moon occurs in the same place at the node. a lunar occultation can happen. These two nodes allow two to five occultations per twelvemonth. parted by about six months. ( Note: Not drawn to scale. The Sun is much larger and farther off than the Moon. )

A entire penumbral lunar occultation dims the Moon in direct proportion to the country of the sun’s disc blocked by the Earth. This comparing shows the southern shadow penumbral lunar occultation ofJanuary 1999 ( left ) to the same Moon outside of the shadow ( right ) demonstrates this elusive dimming. The shadow of the Earth can be divided into two typical parts: the umbra andpenumbra. Within the umbra. there is no direct solar radiation. However. as a consequence of the Sun’s big angular size. solar light is merely partly blocked in the outer part of the Earth’s shadow. which is given the name penumbra. A penumbral occultation occurs when the Moon base on ballss through the Earth’s penumbra. The penumbra causes a elusive blackening of the Moon’s surface. A particular type of penumbral occultation is a entire penumbral occultation. during which the Moon lies entirely within the Earth’s penumbra. Entire penumbral occultations are rare. and when these occur. that part of the Moon which is closest to the umbra can look slightly darker than the remainder of the Moon.

A partial lunar occultation occurs when merely a part of the Moon enters the umbra. When the Moon travels wholly into the Earth’s umbra. one observes a entire lunar occultation. The Moon’s velocity through the shadow is about one kilometre per second ( 2. 300 miles per hour ) . and entirety may last up to about 107 proceedingss. However. the entire clip between the Moon’s foremost and last contact with the shadow is much longer. and could last up to 4 hours. [ 1 ] The comparative distance of the Moon from the Earth at the clip of an occultation can impact the eclipse’s continuance. In peculiar. when the Moon is near its culmination. the farthest point from the Earth in its orbit. its orbital velocity is the slowest. The diameter of the umbra does non diminish appreciably within the alterations in the orbital distance of the Moon. Thus. a wholly eclipsed Moon happening near culmination will lengthen the continuance of entirety.

The timing of entire lunar occultations are determined by its contacts: [ 2 ]

P1 ( First contact ) : Beginning of the penumbral occultation. The Earth’s penumbra touches the Moon’s outer limb. U1 ( Second contact ) : Beginning of the partial occultation. The Earth’s umbra touches the Moon’s outer limb. U2 ( Third contact ) : Beginning of the entire occultation. The Moon’s surface is wholly within the Earth’s umbra. Greatest occultation: The peak phase of the entire occultation. The Moon is at its closest to the centre of the Earth’s umbra. U3 ( Fourth contact ) : End of the entire occultation. The Moon’s outer limb exits the Earth’s umbra. U4 ( Fifth contact ) : End of the partial occultation. The Earth’s umbra leaves the Moon’s surface. P2 ( Sixth contact ) : End of the penumbral occultation. The Earth’s shadow no longer makes any contact with the Moon.

Selenelion

A selenelion or selenehelion occurs when both the Sun and the eclipsed Moon can be observed at the same clip. This can merely go on merely earlier sunset or merely after dawn. and both organic structures will look merely above the skyline at about opposite points in the sky. This agreement has led to the phenomenon being referred to as a horizontal occultation. There are typically a figure of high ridges undergoing dawn or sunset that can see it. Indeed. the crimson visible radiation that reaches the Moon comes from all the coincident dawns and sundowns on the Earth. Although the Moon is in the Earth’s umbra. the Sun and the eclipsed Moon can both be seen at the same clip because the refraction of visible radiation through the Earth’s atmosphere causes each of them to look higher in the sky than their true geometric place. [ 3 ]

The Moon does non wholly disappear as it passes through the umbra because of therefraction of sunshine by the Earth’s atmosphere into the shadow cone ; if the Earth had no ambiance. the Moon would be wholly dark during an occultation. The ruddy colouring arises because sunshine making the Moon must go through through a long and heavy bed of the Earth’s ambiance. where it is scattered. Shorter wavelengths are more likely to be scattered by the air molecules and the little atoms. and so by the clip the visible radiation has passed through the ambiance. the longer wavelengths dominate. This ensuing visible radiation we perceive as ruddy. This is the same consequence that causes sundowns and dawns to turn the sky a ruddy colour ; an alternate manner of sing the job is to recognize that. as viewed from the Moon. the Sun would look to be puting ( or lifting ) behind the Earth.

The sum of refracted light depends on the sum of dust or clouds in the ambiance ; this besides controls how much visible radiation is scattered. In general. the dustier the ambiance. the more that other wavelengths of visible radiation will be removed ( compared to red visible radiation ) . go forthing the ensuing visible radiation a deeper ruddy colour. This causes the ensuing coppery-red chromaticity of the Moon to change from one occultation to the following. Vents are noteworthy for throw outing big measures of dust into the ambiance. and a big eruption shortly before an occultation can hold a big consequence on the ensuing colour.

Danjon graduated table

The undermentioned graduated table ( the Danjon graduated table ) was devised by Andre Danjon for evaluation the overall darkness of lunar occultations: [ 4 ]

L=0: Very dark occultation. Moon about unseeable. particularly at mid-totality. L=1: Dark occultation. grey or brownish in colour. Details distinguishable merely with trouble. L=2: Deep ruddy or rust-colored occultation. Very dark cardinal shadow. while outer border of umbra is comparatively bright. L=3: Brick-red occultation. Umbral shadow normally has a bright or xanthous rim. L=4: Very bright copper-red or orange occultation. Umbral shadow is blue and has a really bright rim.

Eclipse rhythms

See besides: Saros ( uranology ) and Eclipse rhythm Every twelvemonth there are at least two lunar occultations. although entire lunar occultations are significantly less common.
If one knows the day of the month and clip of an occultation. it is possible to foretell the happening of other occultations utilizing an eclipse rhythm like the saros.

Gallery

The beginning of the November 2003 lunar occultation

December 21. 2010 Lunar Eclipse

This diagram shows how the Moon appears ruddy orange during a lunar occultation.

Painting by Lucien Rudaux. demoing what a lunar occultation might look like when viewed from the surface of the Moon. The moon’s surface appears ruddy because the lone sunshine available is refracted through the Earth’s ambiance on the borders of the Earth. as shown in the sky in this picture.

Lunar occultation in mythology

Several civilizations have myths related to lunar occultations. The Egyptians saw the occultation as a sow get downing the Moon for a short clip ; other civilizations view the occultation as the Moon being swallowed by other animate beings. such as a panther in Mayan tradition. or a three legged frog in China. Some societies thought it was a devil get downing the Moon. and that they could trail it off by throwing rocks and expletives at it. [ 5 ]

Lunar occultation

From Wikipedia. the free encyclopaedia

For other utilizations. see Lunar occultation ( disambiguation ) .
Not to be confused with Solar occultation.

The June 2011 sum occultation
A lunar occultation occurs when the Moon base on ballss straight behind the Earth into its umbra ( shadow ) . This can happen merely when the Sun. Earth. and Moon are aligned ( in “syzygy” ) precisely. or really closely so. with the Earth in the center. Hence. a lunar occultation can merely happen the dark of a full Moon. The type and length of an occultation depend upon the Moon’s location relation to its orbital nodes. Unlike a solar occultation. which can merely be viewed from a certain comparatively little country of the universe. a lunar occultation may be viewed from anyplace on the dark side of the Earth. A lunar occultation lasts for a few hours. whereas a entire solar occultation stopping points for merely a few proceedingss at any given topographic point. due to the smaller size of the moon’s shadow. Besides unlike solar occultations. lunar occultations are safe to see without any oculus protection or particular safeguards. as they are no brighter ( so dimmer ) than the full Moon itself.

Contentss [ hide ] 1 Types of lunar occultation 1. 1 Selenelion 1. 2 Danjon graduated table 2 Eclipse rhythms 3 Gallery 4 Lunar occultation in mythology 5 See besides 6 Mentions
Further reading 8 External links

Types of lunar occultation

Conventional diagram of the shadow dramatis personae by the Earth. Within the cardinal umbra shadow. the Moon is wholly shielded from direct light by the Sun. In contrast. within the penumbrashadow. merely a part of sunshine is blocked.

As seen by an perceiver on Earth on the fanciful celestial domain. the Moon crosses the ecliptic every orbit at places called nodes twice every month. When the full Moon occurs in the same place at the node. a lunar occultation can happen. These two nodes allow two to five occultations per twelvemonth. parted by about six months. ( Note: Not drawn to scale. The Sun is much larger and farther off than the Moon. )

A entire penumbral lunar occultation dims the Moon in direct proportion to the country of the sun’s disc blocked by the Earth. This comparing shows the southern shadow penumbral lunar occultation ofJanuary 1999 ( left ) to the same Moon outside of the shadow ( right ) demonstrates this elusive dimming. The shadow of the Earth can be divided into two typical parts: the umbra andpenumbra. Within the umbra. there is no direct solar radiation. However. as a consequence of the Sun’s big angular size. solar light is merely partly blocked in the outer part of the Earth’s shadow. which is given the name penumbra. A penumbral occultation occurs when the Moon base on ballss through the Earth’s penumbra. The penumbra causes a elusive blackening of the Moon’s surface. A particular type of penumbral occultation is a entire penumbral occultation. during which the Moon lies entirely within the Earth’s penumbra. Entire penumbral occultations are rare. and when these occur. that part of the
Moon which is closest to the umbra can look slightly darker than the remainder of the Moon.

A partial lunar occultation occurs when merely a part of the Moon enters the umbra. When the Moon travels wholly into the Earth’s umbra. one observes a entire lunar occultation. The Moon’s velocity through the shadow is about one kilometre per second ( 2. 300 miles per hour ) . and entirety may last up to about 107 proceedingss. However. the entire clip between the Moon’s foremost and last contact with the shadow is much longer. and could last up to 4 hours. [ 1 ] The comparative distance of the Moon from the Earth at the clip of an occultation can impact the eclipse’s continuance. In peculiar. when the Moon is near its culmination. the farthest point from the Earth in its orbit. its orbital velocity is the slowest. The diameter of the umbra does non diminish appreciably within the alterations in the orbital distance of the Moon. Thus. a wholly eclipsed Moon happening near culmination will lengthen the continuance of entirety.

The timing of entire lunar occultations are determined by its contacts: [ 2 ]

P1 ( First contact ) : Beginning of the penumbral occultation. The Earth’s penumbra touches the Moon’s outer limb. U1 ( Second contact ) : Beginning of the partial occultation. The Earth’s umbra touches the Moon’s outer limb. U2 ( Third contact ) : Beginning of the entire occultation. The Moon’s surface is wholly within the Earth’s umbra. Greatest occultation: The peak phase of the entire occultation. The Moon is at its closest to the centre of the Earth’s umbra. U3 ( Fourth contact ) : End of the entire occultation. The Moon’s outer limb exits the Earth’s umbra. U4 ( Fifth contact ) : End of the partial occultation. The Earth’s umbra leaves the Moon’s surface. P2 ( Sixth contact ) : End of the penumbral occultation. The Earth’s shadow no longer makes any contact with the Moon.

Selenelion

A selenelion or selenehelion occurs when both the Sun and the eclipsed Moon can be observed at the same clip. This can merely go on merely earlier sunset or merely after dawn. and both organic structures will look merely above the skyline at about opposite points in the sky. This agreement has led to the phenomenon being referred to as a horizontal occultation. There are typically a figure of high ridges undergoing dawn or sunset that can see it. Indeed. the crimson visible radiation that reaches the Moon comes from all the coincident dawns and sundowns on the Earth. Although the Moon is in the Earth’s umbra. the Sun and the eclipsed Moon can both be seen at the same clip because the refraction of visible radiation through the Earth’s atmosphere causes each of them to look higher in the sky than their true geometric place. [ 3 ]

The Moon does non wholly disappear as it passes through the umbra because of therefraction of sunshine by the Earth’s atmosphere into the shadow cone ; if the Earth had no ambiance. the Moon would be wholly dark during an occultation. The ruddy colouring arises because sunshine making the Moon must go through through a long and heavy bed of the Earth’s ambiance. where it is scattered. Shorter wavelengths are more likely to be scattered by the air molecules and the little atoms. and so by the clip the visible radiation has passed through the ambiance. the longer wavelengths dominate. This ensuing visible radiation we perceive as ruddy. This is the same consequence that causes sundowns and dawns to turn the sky a ruddy colour ; an alternate manner of sing the job is to recognize that. as viewed from the Moon. the Sun would look to be puting ( or lifting ) behind the Earth.

The sum of refracted light depends on the sum of dust or clouds in the ambiance ; this besides controls how much visible radiation is scattered. In general. the dustier the ambiance. the more that other wavelengths of visible radiation will be removed ( compared to red visible radiation ) . go forthing the ensuing visible radiation a deeper ruddy colour. This causes the ensuing coppery-red chromaticity of the Moon to change from one occultation to the following. Vents are noteworthy for throw outing big measures of dust into the ambiance. and a big eruption shortly before an occultation can hold a big consequence on the ensuing colour.

Danjon graduated table

The undermentioned graduated table ( the Danjon graduated table ) was devised by Andre Danjon for evaluation the overall darkness of lunar occultations: [ 4 ]

L=0: Very dark occultation. Moon about unseeable. particularly at mid-totality. L=1: Dark occultation. grey or brownish in colour. Details distinguishable merely with trouble. L=2: Deep ruddy or rust-colored occultation. Very dark cardinal shadow. while outer border of umbra is comparatively bright. L=3: Brick-red occultation. Umbral shadow normally has a bright or xanthous rim. L=4: Very bright copper-red or orange occultation. Umbral shadow is blue and has a really bright rim.

Eclipse rhythms

See besides: Saros ( uranology ) and Eclipse rhythm Every twelvemonth there are at least two lunar occultations. although entire lunar occultations are significantly less common. If one knows the day of the month and clip of an occultation. it is possible to foretell the happening of other occultations utilizing an eclipse rhythm like the saros.

Gallery

The beginning of the November 2003 lunar occultation

December 21. 2010 Lunar Eclipse

This diagram shows how the Moon appears ruddy orange during a lunar occultation.

Painting by Lucien Rudaux. demoing what a lunar occultation might look like when viewed from the surface of the Moon. The moon’s surface appears ruddy because the lone sunshine available is refracted through the Earth’s ambiance on the borders of the Earth. as shown in the sky in this picture.

Lunar occultation in mythology

Several civilizations have myths related to lunar occultations. The Egyptians saw the occultation as a sow get downing the Moon for a short clip ; other civilizations view the occultation as the Moon being swallowed by other animate beings. such as a panther in Mayan tradition. or a three legged frog in China. Some societies thought it was a devil get downing the Moon. and that they could trail it off by throwing rocks and expletives at it. [ 5 ]