APOD: Solar Eclipse from Uganda (2013 Nov 08)

[APOD Robot]

Solar Eclipse from Uganda

Explanation: The Sun's disk was totally eclipsed for a brief 20 seconds as the Moon's dark umbral shadow raced across Pokwero in northwestern Uganda on November 3rd. So this sharp telescopic view of totality in clear skies from the central African locale was much sought after by eclipse watchers. In the inspiring celestial scene the Moon just covers the overwhelmingly bright photosphere, the lower, normally visible layer of the Sun's atmosphere. Extending beyond the photosphere, the reddish hydrogen alpha glow of the solar chromosphere outlines the lunar silhouette, fading into the Sun's tenuous, hot, outer atmosphere or corona. Planet-sized prominences reaching beyond the limb of the active Sun adorn the edges of the silhouette, including a cloud of glowing plasma separated from the chromosphere near the 1 o'clock position.

<< Previous APOD

This Day in APOD

Next APOD >>

[/b]

[Beyond]

That's pretty much a pink ring around the moon, on my monitor.

[neufer]

---

Hybrid Eclipse Shades Africa
Earth Observatory, November 5, 2013

<<The last eclipse of 2013 was an unusual one. Known as a hybrid eclipse, the Moon blocked just part of the Sun—an annular eclipse—at sunrise in the western Atlantic Ocean, and then moved into total eclipse along a long, narrow path crossing into central Africa. For a little more than three hours, the shadow of the Moon traced a path about 13,600 kilometers long but no more than 58 kilometers wide.

This image shows one orbital swath from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. The yellow line shows the path of the total eclipse, while the map provides context for the location relative to central Africa. VIIRS captured this image at 13:25 Universal Time (1:25 p.m. local time) on November 3, 2013, about 38 minutes after the maximum eclipse. The darkened area is a combination of the umbra (full) and antumbra (partial) shadow of the Moon on Earth’s surface. Skywatchers within the umbra observed a total eclipse that lasted as long as 99 seconds at maximum eclipse, which occurred at 12:47 Universal Time.

Fred Espenak, an eclipse expert at NASA’s Goddard Space Flight Center, described the blend of a partial and total eclipse. “The duality comes about when the vertex of the Moon's umbral shadow pierces Earth’s surface at some locations, but falls short of the planet along other sections of the path. The unusual geometry is due to the curvature of Earth’s surface that brings some geographic locations into the umbra while other positions are more distant and enter the antumbral rather than umbral shadow.” The 2013 event was even more unusual because the eclipse shifted from partial to annular to total and then ended. Hybrid eclipses typically start as annular, become total, and then finish as annular.>>

[Boomer12k]

Ring of Fire!!!!!!

:---[===] *

[MalcolmP]

QUOTE "the Sun's tenuous, , , , , corona."

Very tenuous indeed, one might even ask "where did it go ?" :-!)

Normally, especially during solar max, pics. like this show at least a diameter or two of corona and with streamers following magnetic 'lines' making it easy to see where the poles are.

Is the lack of a corona in this pic due to the exposure, or is it because this is a very minimum maximum (if u c what I mean !)

Any links to other (total)pics of this eclipse anywhere ?

[owlice]

Any links to other pics of this eclipse anywhere ?

Yes, right here: http://asterisk.apod.com/viewtopic.php?f=29&t=32391

[MalcolmP]

Thanks Owl,
(I was editing my post to say "(total) pics" when you were replying ! )

thanks, good thread,
this nice one, by Alson Wong, is the sort of thing I had in mind, but even that does not show the usual polar tracery.
http://i10.photobucket.com/albums/a120/ ... 1383540451
from
http://asterisk.apod.com/viewtopic.php? ... 91#p212745

[AlanOwl]

The chromosphere and prominences show as pinkish in this photo, and I recall being surprised that prominences looked pink visually during the July 11, 1991, total solar eclipse. Through a solar H-alpha telescope prominences and the chromosphere appear very red, obviously because the filters are designed to pass only a very narrow slice (0.5 to 0.7 Angstroms wide, typically) of light at 656.28nm.

What additional contributions cause the prominences to look pinkish during the rare instances - total solar eclipses - when they can be observed safely without a filter?

Thanks, and clear skies, Alan

[Chris Peterson]

The chromosphere and prominences show as pinkish in this photo, and I recall being surprised that prominences looked pink visually during the July 11, 1991, total solar eclipse. Through a solar H-alpha telescope prominences and the chromosphere appear very red, obviously because the filters are designed to pass only a very narrow slice (0.5 to 0.7 Angstroms wide, typically) of light at 656.28nm.

What additional contributions cause the prominences to look pinkish during the rare instances - total solar eclipses - when they can be observed safely without a filter?

Spectral observations of prominences reveal a variety of emission lines besides H-alpha- lines from helium, calcium, sodium, and others. In addition, you have a white background from the corona which reduces the apparent saturation. The net visual effect ranges from pink to orange, depending on the observer and, I presume, slight variations in observing conditions. I've also seen prominences during total eclipses as pink, and photographed them that way, as well.

[JuanAustin]

Is there any other place in the solar system where a solar eclipse appears exactly as ours do? Not to get philosophical about it if that's the right word to use, but how coincidental is it that our moon just happens to be at such a distance that it perfectly matches the disk of the sun almost exactly and get to see the ring the way that we do? How much longer will it take for the orbit of the moon to change enough that we won't be able to see them like this any more?

[Chris Peterson]

Is there any other place in the solar system where a solar eclipse appears exactly as ours do?

Not that I know of. But there are many possible combinations of planets and moons, so it's possible.

Not to get philosophical about it if that's the right word to use, but how coincidental is it that our moon just happens to be at such a distance that it perfectly matches the disk of the sun almost exactly and get to see the ring the way that we do?

"Coincidence" isn't really the right word. If you're going to use that word, however, it would be better applied to the fact that the position of the Moon is what it is just at the time when we, as humans, are able to make note of it.

How much longer will it take for the orbit of the moon to change enough that we won't be able to see them like this any more?

Around a half billion years before they are all annular. So as long as humans exist, there will be good solar eclipses.

[AlanF]

It's certainly possible to see frequent solar eclipses from Jupiter (if you could stand on the upper atmosphere). Its moons are in the same plane as its orbit, and we frequently see the shadows of the larger moons, Io, Europa, Ganymede, and Callisto cast onto the planet's cloud tops. Tomorrow morning, for example, we could see Io and Europa and their shadows cross the face of Jupiter.

But the question was whether the eclipses are like those seen here on Earth. From Jupiter, the Sun's apparent diameter varies from 5.9 to 6.4 arc minutes. From Jupiter the average apparent size (from the cloud tops) of Io is 36.1 arc minutes, Europa is 18.0 arc minutes, Ganymede is 18.2 arc minutes, and Callisto is 9.2 arc minutes. They all appear larger than the Sun. Their orbits are not eccentric enough to change their apparent sizes much.

Even it if was possible from Jupiter, I suspect the much smaller Sun would make the event far less impressive.

I recall reading a science fiction short story, probably from the 1950s or 60s, about a solar eclipse. The kicker was that aliens were here to see it (quietly). I don't recall the author or title, and a quick Google search did not turn up any clues.

Clear skies, Alan

[neufer]

Is there any other place in the solar system where a solar eclipse appears exactly as ours do?

Not that I know of. But there are many possible combinations of planets and moons, so it's possible.It's certainly possible to see frequent solar eclipses from Jupiter (if you could stand on the upper atmosphere). Its moons are in the same plane as its orbit, and we frequently see the shadows of the larger moons, Io, Europa, Ganymede, and Callisto cast onto the planet's cloud tops. Tomorrow morning, for example, we could see Io and Europa and their shadows cross the face of Jupiter.

But the question was whether the eclipses are like those seen here on Earth. From Jupiter, the Sun's apparent diameter varies from 5.9 to 6.4 arc minutes. From Jupiter the average apparent size (from the cloud tops) of Io is 36.1 arc minutes, Europa is 18.0 arc minutes, Ganymede is 18.2 arc minutes, and Callisto is 9.2 arc minutes. They all appear larger than the Sun. Their orbits are not eccentric enough to change their apparent sizes much.

Click to view full size image

To get further away (as well as to actually stand on a solid surface) one must observe the solar eclipse by one Galilean moon from the surface of another.

From Ganymede one can observe a 5.9 to 6.4 arc minute Callisto when their orbital phases are ~130° apart.

From Callisto one can observe a 5.9 to 6.4 arc minute Io when their orbital phases are ~107° apart.

From Callisto one can observe a 5.9 to 6.4 arc minute Europa when their orbital phases are ~68° apart.

From Callisto one can observe a 6.15+ arc minute Ganymede when it is just above the surface of Jupiter.

The trick is to get the alignments to work out.

[JuanAustin]

thanks, everyone! just another fortunate happenstance of being the luckiest species in the universe (so far).
if there was a "Like" option on these pages, i would surely indicate it for all your answers!

[Cousin Ricky]

Is the lack of a corona in this pic due to the exposure, or is it because this is a very minimum maximum (if u c what I mean !)

Two words: “dynamic range.” Briefly, it’s the exposure, although that isn’t the whole story.

The range of brightness of the corona far exceeds the range of photographic media, but our eyes deal with it very well. Before the advent of digital photography and image processing software, it was extremely difficult to capture an image that conveyed the same impression as viewing it in person. (It was less than 20 years ago that I first saw a photograph of a total solar eclipse that really captured the essence of a visual image, and it took the photographer a lot of preparation and months of post-processing to accomplish it.)

[neufer]

[b][color=#0000FF] Angular size ratio between the eclipsing moon and the Sun for each saturnian annual and total mutual eclipse, in chronological order from bottom to top.[/color][/b]

---

[b][color=#0000FF]Artist's conception of the total solar eclipse of Mimas by Tethys on 12 May 2009 as viewed from the surface of Mimas. During this eclipse the rings of Saturn obscure a large fraction of the Sun's corona. (Michael Carroll)[/color][/b]

---

[b][color=#0000FF]Simulation of the start of a minute long solar eclipse by Tethys from Mimas[/color][/b]

---

Mutual eclipses in the solar system
Guillermo Gonzalez

<<Among the first six major moons of Saturn, there are 76 total, 16 annular and 48 partial mutual eclipses during the current eclipse season. We did not include Hyperion in these calculations, because its orbit is not as accurately known as Saturn's other major moons. We plot in figure 3 the magnitudes of its annular and total mutual eclipses. Four of the total mutual eclipses are comparable in magnitude to the typical terrestrial solar eclipse. Three of these are eclipses of Tethys by Mimas and the fourth is an eclipse of Rhea by Enceladus. The busiest date for the saturnian mutual eclipses is 26 July 2009, when nine eclipses take place in just 13 hours.>>

[Anthony Barreiro]

This is a beautiful picture! The Moon so perfectly covers the Sun's photosphere, leaving the chromosphere visible all around the edges of the Moon! This made for a narrower eclipse path and a shorter total eclipse than if the Moon had been closer to the Earth, but a much prettier picture! Thank you Jaime Vilinga! (And, for good measure: )