The Annular Eclipse of May 20 2012

Being the second major solar eclipse event of 2012, the annular eclipse of May 20, 2012 is sure to bring about some impressive photographs as the moon passes in front of the sun. Unlike typical solar eclipses, annulars constitute a niche in astronomical classification for eclipse not only because of their rarity, but mostly because of their peculiarity. An eclipse, loosely defined, occurs when the moon passes in front of the sun, leaving a certain place on earth with no or some part of the sun, as seen by inhabitants of a region. The moon literally blocks out part of the sun for observers. However, depending whether the moon is at apogee and perigee can help define whether such an event will be annular or not. As defined in Matthew Winter's Astronomical Events: Eclipses, Transits, Occultations and Conjunctions, we get a good picture on the elements of an annular eclipse.

It [an annular solar eclipse] is defined as ‘a solar eclipse in which the Moon's antumbral shadow traverses Earth (the Moon is too far from Earth to completely cover the Sun). During the maximum phase of an annular eclipse, the Sun appears as a blindingly bright ring surrounding the Moon,’ from NASA’s Glossary of Solar Eclipse Terms. Annular eclipses are straightforward as well; the moon is fully inside the Sun’s disk, but does not cover it. This is because the moon is at perigee. The closer the earth to the moon, the more frequent the annular eclipse. The sun appears as a great ring, because the moon’s orbit is not completely circular, rather it’s an ellipse that travels in an oval. Unfortunately, the Sun’s corona is lost, but a few phenomena occur; annular eclipses only produce shadow bands, but are usually hard to see, even if any occur. It cannot produce Baily’s beads or the diamond-ring affect, because those can only happen under complete totality. So, on occasions, shadow bands will come into view, but don’t count on it. They’re blurry and difficult to relate to if you see any.

In short, annular eclipses have only one important criterion that must be met in order to form such an event: the moon must be at perigee, or farthest from the sun; only then can the sun be seen as a complete ring, which was named accordingly. (Annulus is the Latin word for "ring"). 

Visibility for the May 20, 2012 eclipse

Statistics for this eclipse, the visibility and frequency of others of its kind, are great. Visibility entails where the event will be able to be seen: from Eastern China across the Pacific Ocean to the Southwestern States are among the multitude of places that spectators will be able to witness the eclipse. "In the United States, the eclipse begins at 5:30 pm PDT and lasts for two hours. Around 6:30 pm PDT, the afternoon sun will become a luminous ring in places such as Medford, Oregon; Chico, California; Reno, Nevada; St. George, Utah; Albuquerque, New Mexico, and Lubbock, Texas. Outside the narrow center line, the eclipse will be partial. Observers almost everywhere west of the Mississippi will see a crescent-shaped sun as the Moon passes by off-center," Spaceweather.com comments. The point of greatest visibility will take place just south of the Aleutian Islands in the North Pacific for five minutes and forty-six seconds. This will be the place where the ring, or annulus, will be seen the greatest.

Taking part in Saros Cycle 128, the annular eclipse of May 20 2012 repeats every eighteen years and eleven days, altogether containing 73 events. "Solar eclipses of Saros 128 all occur at the Moon’s descending node and the Moon moves northward with each eclipse. The series began with a partial eclipse in the southern hemisphere on 0984 Aug 29. The series will end with a partial eclipse in the northern hemisphere on 2282 Nov 01. The total duration of Saros series 128 is 1298.17 years," NASA's eclipse website propagates. For more about Saros 128, NASA's eclipse website's database is superb. More information about Saros can be found there as well. 

When viewing this annular eclipse, like any other solar eclipse, it is important that one realizes the safety precautions that need to be made known. Do NOT attempt to look at the sun without the appropriate filter (or even sunglasses), because of the high risk for blindness. Many astronomical websites have stores where you can buy the appropriate equipment for viewing the sun.

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Recommended links for further information

NASA’s eclipse web site http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2012May20Agoogle.html

Detailed weather reports for this eclipse at Jay Anderson’s web site, http://eclipser.ca/

Descriptions and interactive maps by Bill Kramer at http://www.eclipse-chasers.com/tseNext.php?TSE=ase2012d

Interactive Google map by Xavier Jubier at  http://xjubier.free.fr/en/site_pages/solar_eclipses/ASE_20120520_pg01.html.

National Astronomical Observatory of Japan: http://naojcamp.mtk.nao.ac.jp/phenomena/20120521/summary-en.html

U.S. Naval Observatory and HM Nautical Almanac Office: http://astro.ukho.gov.uk/eclipse/0132012/

Stellar Occultations for April 25-26

For two days this April, two different 3-4 magnitude stars will occult for Western Africa both times, with a plethora of other locations on each separate dates. With the moon waxing after being full April 21, the stars should not be too difficult to see and should provide a wonderful show for spectators.

APRIL 25, 2012: OCCULTATION OF ζ TAURUS

 

The moon will only be 17% illuminated when this occultation of Zeta Taurus occurs, giving Western Europe and Africa a wonderful seat. France, Spain, Italy, Germany, (part of) England, and most of the north-western coast of Africa are just a few of the many locations (you can find ephemerides here) the occultation will be visible. Zeta Taurus is a binary star of the 3.010 magnitude on the far right side of the zodiacal constellation of Taurus, situated approximately 440 light-years from earth; although without highly-technological equipment the two stars that comprise Zeta Taurus will cannot be discerned, it is bright enough to be seen with the naked eye, but binoculars or a telescope will make the event more expressive. 

APRIL 26, 2012: OCCULTATION OF γ GEMINI

Although the visibility of the occultation is practically the same as the occultation yesterday (April 25, above), most of north-western Europe will not be able to see Gamma Gemini be occulted by the moon. With a moon illumination of 25 percent, it is the prime time for this rather-dim star to occult: it being at 4.1, according to IOTA stellar occultations, ephemerides for locations of this occultation here. Western Africa will be the prime location for this event, as most of Africa's north-western part is in the visibility zone.

Partial Solar Eclipse for November 25, 2011

It's the last eclipse of the 2011 Solar Eclipse season; make it meaningful. November 25, 2011 will bring us another partial solar eclipse, and this time over Antarctica, so a plethora of images won't come in. The moon will obscure 90.5% of the sun, making it a very good partial solar eclipse, so this should be picture-worthy if only we had photographers who lived in Antarctica. Yes, the July 1, 2011 eclipse was the same (no-one will be in the location of the eclipse), but nonetheless that eclipse did not block out so much sun as this eclipse will. NASA! Eclipse Webpage.

 

Belonging to Saros 123, this eclipse will be seen over New Zealand, the tip of Africa, and of course Antarctica, while the greatest eclipse occurs at 06:20:17 UT with a magnitude of 0.905 near the coast of Antarctica at latitude -68° 34.1’, longitude +82° 24’. It starts at 04:23:14 UT, and ends at 08:17:16 UT. For pure theoretical interest; "This is the 53rd eclipse of Saros 123. The family began with 6 partial eclipses from the years 1074 to 1164. By the time the series ends in 2318, it will have produced 70 eclipses in the following order: 6 partial, 27 annular, 3 hybrid, 14 total, and 20 partial eclipses. Complete details for Saros 123 can be found here." (Thanks to NASA)

Let the Eclipse Begin!
DEFECTUS INCIPIAT!