APOD: Cheering a Total Solar Eclipse (2016 Mar 15)

[APOD Robot]

Cheering a Total Solar Eclipse

Explanation: What would you do if you saw the Sun disappear? Quite possibly: cheer. That's what many exuberant sky watchers did across Indonesia during a total eclipse of the Sun last week. There and then, the land and sky went dark during the day as our Sun disappeared for a few minutes behind our Moon. Many people watching knew they were witnessing a rare event, and their joyous exclamations can be heard on the featured video. What a far cry this reaction is from centuries ago, when more typical eclipse reactions derived from fear and worry. The video shows first shows a Sun only partly eclipsed by the Moon as totality approached. From many locations, foreground clouds on our Earth either obscured the view or made the view more interesting. The total eclipse was only visible from a narrow swath of Earth that included several Indonesian islands. At the same time, in the opposite direction, NASA's EPIC camera aboard NOAA's DSCOVR satellite captured the shadow of the Moon moving across the Earth.

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[Qweenie]

I am wondering if the narrowness of the corona show here is an artifact of the photography or if it is really reduced compared to previous eclipses. I understand are entering a 'quiet sun' period but it's early in this part of the solar cycle.

[Bric]

In the DISCOVR video of the moon's shadow crossing the Earth, why is the shadow so diffuse? I understand the Earth's atmosphere scatters the light, but that should only be apparent from the ground. From space, it seems that the edges of the moon's shadow should be quite distinct. Or is it just a function of the moon's distance?

[rochelimit]

I am wondering if the narrowness of the corona show here is an artifact of the photography or if it is really reduced compared to previous eclipses. I understand are entering a 'quiet sun' period but it's early in this part of the solar cycle.

I don't know if you have seen corona before with your own eyes, but I was there in Indonesia during the event. No photograph or video can depicts the glory of corona with your own eyes. The corona is big, very thin however, but you can distinguish the loop and all, almost like a flower. Some superstitious people of Indonesia think that they can see the Arab word of God (Allah) in the corona, and I can understand that because the word Allah in Arabic has this prominent loops that can be replicated with the shape of this solar eclipse. The would appear with your own eyes more or less like this. http://www.stellar-explosions.com/wp-co ... ample1.jpg

The moon is blue, you can see the bluish earthshine, and the corona is the best because you see some corona are shaped like prominence, a bit arching. Quiet the experience, my cheer was OH MY GOD!!! OH MY GOD!!! it was unreal!

[NGC3314]

In the DISCOVR video of the moon's shadow crossing the Earth, why is the shadow so diffuse? I understand the Earth's atmosphere scatters the light, but that should only be apparent from the ground. From space, it seems that the edges of the moon's shadow should be quite distinct. Or is it just a function of the moon's distance?

A function of the Moon's size and distance from Earth (plus the Sun's angular size). The tip of the Moon's umbra (total shadow) barely reaches the Earth (and doesn't get all the way here for an annular eclipse), so it's surrounded by a much large region (several thousand km across) where the Sun is partially covered (the penumbra), fading out imperceptibly at the edges. The same thing happens to shadows of terrestrial objects if they are small, narrow, or high above the ground. Looking at pictures of the shadows of Jupiter's big moons, for example, is very different - their shadows converge much ore gently because the Sun is father away, so the umbra is almost as large as each Moon (most pronounced for Io on the inside, least for Callisto on the outside). An example image comparing three such shadows from Hubble is here.

[Chris Peterson]

What a far cry this reaction is from centuries ago, when more typical eclipse reactions derived from fear and worry.

As they still are in some places. It was only 20 years ago when I observed a total solar eclipse in Rajastan, and had to deal with a hotel which encouraged its guests to stay in their rooms, under the covers with the curtains drawn and promised to keep all their food sheltered from the "poisoned rays" of the eclipsed Sun. Had to deal with the difficulty of finding a hired car and driver not afraid of the eclipse. And had the surreal experience of all the village women hidden from sight during the eclipse, with their ululations rising from the dunes around me as totality approached.

[Boomer12k]

And we STILL howl at the Moon....

But it was a nice eclipse, even though I did not personally see it...

:---[===] *

[Beyond]

What a far cry this reaction is from centuries ago, when more typical eclipse reactions derived from fear and worry.

As they still are in some places. It was only 20 years ago when I observed a total solar eclipse in Rajastan, and had to deal with a hotel which encouraged its guests to stay in their rooms, under the covers with the curtains drawn and promised to keep all their food sheltered from the "poisoned rays" of the eclipsed Sun. Had to deal with the difficulty of finding a hired car and driver not afraid of the eclipse. And had the surreal experience of all the village women hidden from sight during the eclipse, with their ululations rising from the dunes around me as totality approached.

That must have been quite an experience! I never knew what the sound a lot of mid-eastern women make when something bad happens, is called a ululation. One learns something new at the Asterisk* almost every day.

[rstevenson]

That must have been quite an experience! I never knew what the sound a lot of mid-eastern women make when something bad happens, is called a ululation. One learns something new at the Asterisk* almost every day.

Ululation -- or zaghareet, in Arab regions -- is not always used in bad situations. It is often celebratory, and is used socially, especially but not exclusively, among women. The sound is common in cultures from North Africa all the way to South-East Asia. And lately, of course, it is becoming more common world-wide, as people from these regions continue to move around the world.

Rob

[neufer]

What a far cry this reaction is from centuries ago, when more typical eclipse reactions derived from fear and worry.

As they still are in some places. It was only 20 years ago when I observed a total solar eclipse in Rajastan, and had to deal with a hotel which encouraged its guests to stay in their rooms, under the covers with the curtains drawn and promised to keep all their food sheltered from the "poisoned rays" of the eclipsed Sun. Had to deal with the difficulty of finding a hired car and driver not afraid of the eclipse. And had the surreal experience of all the village women hidden from sight during the eclipse, with their ululations rising from the dunes around me as totality approached.

• . https://en.wikipedia.org/wiki/Solar_ecl ... r_24,_1995
  http://www.mreclipse.com/SEreports/TSE1 ... penak.html
  
  Ululation is primarily celebratory & Arab/Muslim :

<<Ululation is practiced in certain styles of singing, as well as in communal ritual events, used to express strong emotion. In Arab countries ululation is commonly used to express celebration. It is especially used in West Bengal in India, especially during weddings and other auspicious events.>>

• Could they have been Hindu Mantras instead

[img3="Mantras linked with Rahu include
"Om Rang Rahuve Namah Om",
"Om Dhoom Raam Rahave Namaha", and
"Om Bhram Bhreem Bhroum Sah Rahave Namah"."]https://upload.wikimedia.org/wikipedia/ ... ailand.JPG[/img3]

<<In Hindu tradition, Rahu is the severed head of a demon called Svarbhānu ("Splendour of Radiance"), that swallows the sun causing eclipses. He is depicted as a serpent with no body riding a chariot drawn by eight black horses. In Vedic astronomy, Rahu is considered to be a rogue planet. Astronomically, Rahu and Ketu denote the points of intersection of the paths of the Sun and the Moon as they move on the celestial sphere. Therefore, Rahu and Ketu are respectively called the north and the south lunar nodes. The fact that eclipses occur when the Sun and the Moon are at one of these points gives rise to the myth of the swallowing of the Sun and the Moon by the demon snake.

According to legend the Svarbhānu drank some "immortal nectar". When the Sun and the Moon realized it, they alerted Mohini, the female avatar of Vishnu. Mohini cut off Svarbhānu's head before the nectar could pass his throat. The head, however, remained immortal and became Rahu. It is believed that this immortal head from time to time, swallows the Sun, causing eclipses. Then, the sun passes through the opening at the neck, ending the eclipse. The body also turned into Ketu due to a boon, and it in turn, swallows the Moon on timely basis to cause a lunar eclipse.

Rahu does his best to plunge any area of life he controls into chaos, mystery, and cruelty. He is associated with the world of material manifestation and worldly desire, as well as random, uncontrolled growth without wisdom or understanding. It is a legendary master of deception who signifies cheaters, pleasure seekers, operators in foreign lands, drug dealers, poison dealers, insincere and immoral acts.>>

[Chris Peterson]

That must have been quite an experience! I never knew what the sound a lot of mid-eastern women make when something bad happens, is called a ululation. One learns something new at the Asterisk* almost every day. :yes:

Ululation -- or zaghareet, in Arab regions -- is not always used in bad situations. It is often celebratory, and is used socially, especially but not exclusively, among women.

This is a predominently Hindu area, although very close to the Pakistani border. I don't know what the wailing was about, but given the high degree of worry I observed about the eclipse and its effects on people (especially pregnant women) and food, I am fairly certain that in this case the ululation was not celebratory.

[SumGai]

I'm the odd man out here... hate the "woot-wooting" and "OMG" chanting you get from crowds of noisy self-addicts these days.

I'd much prefer to be on a mountain somewhere watching this event in the awesome and beautiful stillness of nature.

[JohnD]

No Bailey's Beads at totality, none at all.
Was the Moon at or near perigee? Closer than usual?

John

[Nitpicker]

What a far cry this reaction is from centuries ago, when more typical eclipse reactions derived from fear and worry.

As they still are in some places. It was only 20 years ago when I observed a total solar eclipse in Rajastan, and had to deal with a hotel which encouraged its guests to stay in their rooms, under the covers with the curtains drawn and promised to keep all their food sheltered from the "poisoned rays" of the eclipsed Sun. Had to deal with the difficulty of finding a hired car and driver not afraid of the eclipse. And had the surreal experience of all the village women hidden from sight during the eclipse, with their ululations rising from the dunes around me as totality approached.

That's an interesting story, Chris. A rare modern reaction to a rare event.

But I like to imagine that there were also rare reactions in ancient times, where at least some observers were as thrilled as most of us modern folk, at the marvelous sight of an eclipse. I'm confident that some even had a reasonable idea of what was happening.

[Nitpicker]

No Bailey's Beads at totality, none at all.
Was the Moon at or near perigee? Closer than usual?

John

At the time of totality, the Moon was about 29 hours shy of its perigee and appeared ~1.25 arcmin larger than the Sun.

(Some beads are apparent to me on this page: http://asterisk.apod.com/viewtopic.php?f=29&t=35703)

[geckzilla]

No Bailey's Beads at totality, none at all.
Was the Moon at or near perigee? Closer than usual?

John

At the time of totality, the Moon was about 29 hours shy of its perigee and appeared ~1.25 arcmin larger than the Sun.

(Some beads are apparent to me on this page: http://asterisk.apod.com/viewtopic.php?f=29&t=35703)

A good composition showing totality and Bailey's beads is here: https://www.flickr.com/photos/steedjoy/ ... ool-apods/

[JohnD]

In both those cases, surely what we see is the "Diamond Ring", that last sliver of Sun as it disappears and then reappears behind the Moon?
Plus a prominence?

But that last sliver might be where a valley on the Moon is roundabout that last arc, so if you want to call it a Bead, fine.
John

[geckzilla]

I do recall having this conversation in the past where you make the strict distinction about Bailey's beads involving the lunar landscape and not any protruding bits of sun. I also think that perhaps the beads have always involved slightly protruding bits of sun and that in the past people presumed they were due to mountains and valleys on the moon and that presumption is false because the sun's "topography" is much more significant than the moon, which appears virtually smooth. Now that we have much better methods of photographing the eclipse we can say hey, where did the Bailey's beads go? Maybe they never existed by that strict definition.

[JohnD]

I think nitpickers answer answers your question geckzilla. "29 hours sort of perigee, and c.1.25 arc-minutes larger than the Sun." With about six months between perigee and apogee, just over a day is spot on!

And an illusion? Surely now with our knowledge of Lunography, it would be possible to predict where the beads will appear, from the deeper valleys and rifts in the Moon on the edge of the visible face. That would be an interesting study!

John

[Nitpicker]

Only a fortnight between perigee and apogee. Six months between perihelion and aphelion.

[JohnD]

But nitpicker, he said, picking a nit...

"Perihelion" and " aphelion" refer to distance from the Sun, and that will change its apparent size, apparently by 3.4%, when I believe that the Moon's apparent size changes by 11%?
But I take your point, that the Moon has a perigee and an apogee once a month. My mistake. Isn't there a variation on that as well, that gives rise to an occasional "Super Moon", and presumably a "Micro Moon"?

John

[Nitpicker]

The Earth was slightly closer to its perihelion (early Jan) than its aphelion at totality.