Posts Tagged ‘Annular Eclipse’

The Eclipse Ring of Fire

19 July, 2009

In eclipse-speak, a Ring of Fire is the view of an annular eclipse of the Sun by the Moon.

(An annular eclipse occurs instead of a total eclipse when the Moon is on the far part of its elliptical orbit around the Earth. It results in the apparent size of the Moon being visibly smaller than the apparent size of the Sun.)

The name is kinda self-explanatory, but its effect is incredibly beautiful: at the peak of the eclipse, the dark Moon will appear to be surrounded by the bright Sun, creating a brilliant, burning “ring”.

This picture of a magnificent “ring of fire” was photographed in January 1992 by Dennis L Mammana and appeared on Astronomy Picture of the Day in January 2009.

Photo: Dennis L Mammana

Wednesday’s eclipse will be a total eclipse. The next annular eclipse will take place in January 2012.

Advertisements

Through the clouds

16 July, 2009

Those catching the eclipse of October 3, 2005 lucked out. The skies were cloudy over Spain, but they still managed to catch this shot of an annular eclipse. In fact, the clouds added a bit of textures to create this amazing shot.

That said… please, please, please, please let the skies be clear on 22 July 2009.

Solar Eclipse 3 Oct 2005 (Photo: Chosovi)

A retro eclipse

15 July, 2009

It’s the 70’s. Some people spread peace and love. Others chase eclipses. Like this one, seen from Santorini, Greece on April 29, 1976.

7 more days to the century’s most dramatic eclipse. Spread the word.

29 Apr 1976 Annular Eclipse (Image: Hans Bernhard)

Moon eats Sun… Like a cookie…

10 July, 2009

Another sequence shot of the annular eclipse of October 3, 2005. This one shot from Gárgoles de Arriba in Spain.

From the silhouette of the Moon descending, it really looks like it just came down and “ate” the Sun before moving off and continuing on its way.

No wonder many of the ancients had tales of the Moon consuming the Sun. (If we had our way, we would have added a bit about “and the Moon chomped up the Sun like a cookie”… But that’s just us…)

Annular Eclipse (Image: Antonio Ferretti)

How rare is “rare”?

10 July, 2009

Annular Eclipse (Photo: Juan Fernandez)Exactly how rare is it to view a total solar eclipse?

While at least two or up to five solar eclipses can happen on Earth every year, they are not all total solar eclipses.

And even when they do happen, they take place only along a narrow strip along our planet. (Sometimes they take place over an ocean and except for those who make a special trip, very few people see them at all.)

On October 3, 2005 an annular eclipse took place in Spain.

(Annular eclipses are like total eclipses because the Moon is in front of the Sun, yet appears visually smaller than the Sun, leaving a border or ring around the dark silhouette of the Moon.)

It was the first total or annular eclipse in Spain since 1748.

So these occurrences are pretty rare. Be sure to catch the one coming up on July 22, 2009, even if it’s in real time via “live” feed on SunStopper.sg.

Annular Eclipse (Photo: Juan Fernandez)

Total vs Annular eclipses

27 May, 2009

While total solar eclipses are awesome, unfortunately, not every eclipse of the Sun is a total eclipse.

Sometimes, the Moon appears smaller than the Sun’s disc, which results in an annular eclipse, where the Sun’s apparent larger size creates a very bright ring, or annulus, around the silhouette of the Moon.

total vs annularThis happens because of the Moon’s orbit around the Earth — it is not perfectly round, but oval, or elliptical, in shape. As the Moon orbits Earth, its distance varies from around between 221,000 to 252,000 miles. (This 13% variation in the Moon’s distance from Earth also explains the Moon’s apparent size in the sky varies by the same amount.)

So, when the Moon is on the near side of its orbit, it appears larger to us than the Sun. If an eclipse happens at that time, it will be a total eclipse. In the umbra shadow, we would see the Moon completely block the Sun. Fig. (A)

However, if the eclipse happens when the Moon is on the far side of its orbit, the Moon will appear smaller than the Sun, and can’t completely cover it, giving us an annular eclipse. The name comes from the annulus, of the bright ring, around the outline of the Moon. On Earth, we would be located in the antumbra shadow. Fig. (B)

In both total and annular eclipses, places that fall in the path of the penumbra will see a partial eclipse. Fig. (C)

Check out these images comparing total eclipses to annular eclipses, where the apparent size of the Moon is the same as the Sun in one, blocking it totally, and smaller than the Sun in another, leaving a ring around the Moon’s silhouette.

01 AUG 2008 Solar_Eclipse_GansuRingfoermigeSonnenfinsternis

What in the world is a solar eclipse?

26 May, 2009

In case you’ve forgotten what you learnt in Solar Eclipse 101, the definition goes like this:

A Solar Eclipse occurs when the Moon passes between the Sun and the Earth so that the Sun is fully or partially obscured.

In English, the Moon’s path crosses in between us and the Sun. When this happens, its shadow falls onto the Earth’s surface. In turn, what we see is the spectacular sight of the dark silhouette of the moon blocking the blinding disc of the Sun.

11 AUG 1999

Photo: Luc Viatour (www.lucnix.be)

Solar eclipses happen between two to five times a year, but they are often not total eclipses. Even if they were, totality occurs only along a narrow corridor in the relatively tiny area of the Moon’s umbra (more on that later). For example, most of the total eclipse that happened in January 26, 2009, fell over the Indian Ocean. (Photo Credit: Luc Viatour)

This makes a total eclipse a rare and spectacular natural phenomenon and many people are willing to travel to remote locations to catch one. The August 11, 1999 solar eclipse that fell over Europe raised global awareness for the phenomenon.

There are four types of solar eclipse:

  • A total eclipse occurs when the Sun is completely obscured by the Moon. The intensely bright disk of the Sun is replaced by the dark silhouette of the Moon, and a faint corona visible. During any one eclipse totality is visible only from at most a narrow track on the surface of the Earth.        

    RingfoermigeSonnenfinsternis

    Photo: NASA

  • An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the outline of the Moon. (More about this later.) 
  • A hybrid eclipse (of annular or total eclipse) transitions between a total and annular eclipse. At some points on the surface of the Earth, it is visible as a total eclipse, whereas at others it is annular. Hybrid eclipses are comparatively rare.
  • A partial eclipse occurs when the Sun and Moon are not exactly in line, and the Moon only partially obscures the Sun. This phenomenon can usually be seen from a large part of the Earth outside the track of an annular or total eclipse. However some eclipses can only be see as a partial eclipse, because the umbra never intersects the Earth’s surface.

The match between the apparent sizes if the Sun and Moon during a total eclipse is a coincidence.

eclipse diagramThe diagram here shows how a total solar eclipse works.

With the Sun, Moon and Earth aligned, the dark gray region below the Moon is the umbra, where the Sun is completely obscured by the Moon.

The small area where the umbra touches the Earth’s surface is where a total eclipse can be seen. The larger light gray area is the penumbra, in which only a partial eclipse can be seen.