A solar eclipse can occur at new moon when the moon passes between the Earth and the Sun. The moon orbits around the Earth once every 29-and-a-half days. However, a solar eclipse does not always happen every new moon.
This is because the orbit of the moon around the Earth is tilted at five degrees to the Earth’s orbit around the Sun called the ecliptic. This results in the moon’s shadow casting above or below the Earth whenever the moon is between the Earth and the Sun.
But at least twice a year the moon is in line with the Earth’s orbital plane around the Sun. This causes the shadow of the moon to fall on the Earth’s surface and the eclipse of the Sun is observed in the region where the shadow falls.
Partial phases of the eclipse on June 11 will be visible in eastern Asia. It can also be observed in the entire Philippines.
On June 11, the moon will rise ahead of the Sun by one minute. The moon will rise at 5:26 a.m., and the Sun at 5:27 a.m. The eclipse will start at 5:11 a.m. when the moon is about four degrees below the horizon.
When the Sun is completely above the horizon, observers will see the upper right disk of the Sun covered by the moon.
The eclipse will be at its maximum at about 6:10 a.m. when the moon covers almost half of the Sun’s disk. Even city observers will have a greater chance of seeing the maximum of the eclipse because the Sun will be about eight degrees above the horizon. The eclipse will progress until 7:07 a.m. when the moon totally uncovers the disk of the Sun.
The best location to view the eclipse is along the beach facing the east or in places where the eastern horizon is free from high-rise obstructions like buildings, trees and even mountains.
The eclipse of the Sun should never be viewed with the naked eye because this may result in permanent damage to the eye or may even lead to blindness.
The Sun should only be viewed using a special filter. One of the most commonly available solar filter is a number 14 welder’s glass which is readily available in hardware stores. A two-by-four-inch glass costs no more than P20.
Never use color film, black and white photographic film, used medical X-ray film, smoked glass or aluminized candy wrapper.
The next solar eclipse is on Dec. 4 this year. It will be a total solar eclipse. The path of the moon’s umbra will begin in the South Atlantic, off the west coast of equatorial Africa, then will cross southern Africa and the Indian Ocean and will end in southern Australia.
The Dec. 4 total eclipse is not visible in the Philippines.
(The author is a member of the Philippine Astronomical Society (PAS). He can be reached at 0919-8558080 and at polaris@speedsurf.pacific.net.ph. The PAS website is at http://www.geocities.com/philastrosoc.)