Penumbral lunar eclipse visible tonight

MANILA, Philippines -- Filipinos can witness a penumbral lunar eclipse tonight should the evening skies permit, state weather forecasters said.

“A penumbral eclipse of the moon will occur on Feb. 9 and it will be visible in the Philippines,” according to the monthly astronomical diary of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa).

Tonight’s activity would be the first of the six lunar eclipse events of the year.

Pagasa said the eclipse would begin when the Moon enters penumbra stage at 8:36 p.m. and ends Tuesday at 12:39 a.m.

Pagasa explained the penumbra refers to a partially shaded outer region of a shadow that an object casts.

A penumbral eclipse occurs when the moon passes through the faint penumbral portion of the earth’s shadow, Pagasa said.

“The lunar surface is not completely shadowed by the earth’s umbra (darkest part of a shadow). Instead, observers see only the slightest dimming near the lunar limb closest to the umbra. The eclipse may be undetectable unless at least half of the moon enters the penumbra,” Pagasa said.

The astronomical event would also be observed in Alaska, Australia, eastern Asia, Hawaii, New Zealand and in the western parts of Canada and the United States.

Pagasa said many penumbral eclipses have few observable effects but tonight’s lunar eclipse “will carry the moon far enough into the light gray shadow to produce a dimming of the northern lunar limb.”

According to National Aeronautics and Space Administration (NASA), this event is the deepest penumbral eclipse in 2009, with a penumbral magnitude of 0.899.

“It will be visible to the naked eye as dusky shading in the northern half of the moon,” Pagasa said.

Last Jan. 26, an annular solar eclipse was observed in the country.

In an annular eclipse, the moon does not completely cover the sun’s face, as it does in a total eclipse.

A solar eclipse occurs when the moon’s shadow crosses the earth’s surface.

Astronomy enthusiasts in the country can also look forward to other celestial events this year - a penumbral lunar eclipses that would occur on July 7 and Aug. 6; a total solar eclipse on July 22 and a partial lunar eclipse on Dec. 31.