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Hybrid Solar Eclipse


8th April 2005 (eclipse date)
By Salvador J. Ribas

Eclipsi sobre una pantalla
This image is a courtesy of the expedition that the University of North Dakota has sent to Panama.

The first solar eclipse of 2005 is of an uncommon type known as either annular-total or hybrid. This is a unique class of central eclipse where some sections of the path are annular while other parts are total. The duality comes about when the vertex of the Moon's umbral shadow pierces the Earth's surface at some points, but falls short of the planet along other sections of the path.

In this case, the central path begins annular, changes to total for the middle portion of the track, and reverts back to annular towards the end of the path. Since these events occur near the vertex of the Moon's umbral/antumbral shadows, the central path is typically quite narrow.

The hybrid eclipse of 2005 will be visible from within a thin corridor, which traverses the Southern Hemisphere. The path of the Moon's shadow begins southeast of New Zealand and stretches across the Pacific Ocean to Panama, Colombia, and Venezuela. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes New Zealand, much of the Southern Pacific and Southern and Northern America.

Informacions sobre el recorregut de l'ombra de l'eclipsi

The central eclipse track begins at 18:54 UT as a 28 kilometre wide annular path with a duration of 28 seconds. However, the path quickly narrows to 0 kilometres within the first 13 minutes of its trajectory some 2200 kilometres south of Tahiti. Continuing along its northeastern course, the path is now total as it rapidly expands in width. Unfortunately, no Pacific islands of any size fall within the path of totality. At 19:48 UT , the umbral shadow passes north and just grazes Oeno Island (near Pitcarn). The 21 kilometre wide path now has a central duration of 31 seconds with the Sun 56° above the horizon.

At greatest eclipse (20:35:46 UT ), the duration of totality is 42 seconds and the path width is 27 kilometres. As the shadow proceeds along its watery trajectory, the path begins to narrow as the length of totality decreases. The path becomes annular again at 22:00 UT about 800 kilometres due north of the Galapagos Islands and 900 kilometres west of Central America. By the time the shadow reaches the coast of Costa Rica (22:09 UT ), the annular phase will already be 12 seconds and growing. The track width increases from 11 to 33 kilometres as it sweeps across Panama, Colombia, and Venezuela. Finally the central path ends in Venezuela where a 33 seconds annular eclipse will occur at sunset (22:18 UT ). Over the course of 3 hours and 24 minutes, the Moon's central shadow traverses a 14,200 kilometre long track covering a scant 0.06% of the Earth's surface area.

This is the 51st eclipse of Saros series 129. The series began with 20 partial eclipses, the first of which was on 1103 Oct 03. The first annular eclipse occurred on 1464 May 06. The series continued to produce annular eclipses until the hybrid eclipse of 1987 Mar 29. Another hybrid will occur in 2023 Apr 20. The following events will all be total eclipses. The series ends with 19 partial eclipses, the last of which occurs on 2528 Feb 21.



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