December 10-11, 2011 Total Lunar Eclipse Observation

This coming December 10-11, 2011, a total lunar eclipse will be visible in its entirely from the Philippines as well as in Asia and Australia. A total lunar eclipse occurs when a full Moon is exactly on the line from the Sun to the Earth. The Moon is then in Earth's shadow, or the umbra, and takes on a reddish or orange color. This coloring comes from light refracted around the edge of Earth towards the Moon; it comes from all Earth's sunrises and sunsets. If Earth's atmosphere is especially opaque, as happens following a major volcanic eruption, the eclipse can be so dark that the Moon disappears, but this is very rare. Since this eclipse happens with the Moon submerged in the Earth's umbral shadow's southernmost edge , the totally eclipsed Moon is expected to be bright compared to last June 16's total lunar eclipse whereas the Moon almost passed through the center of the Earth umbral shadow thus showing a dark red color as seen from the above image taken by ALPer James Kevin Ty last June 16, 2011.

No two lunar eclipses are alike, since there is always some factor that causes variation in the phases, brightness or color; consequently is worthwhile observing each eclipse. One of the best ways to monitor the progress of a lunar eclipse is with binoculars. A telescope will give you a close-up view of the shadow moving slowly over the craters, but with their wide views and sharp optics, binoculars give you a striking perspective on the entire drama of totality.

For this eclipse, penumbral phase will start at around 7:33pm Philippine Standard Time (PST) with the penumbral shadow entering through the eastern portion of the Moon . But the interesting part of this event will happen when the main umbra phase (which is the darkest shadow) will start to casts its shadow at around 8:45pm PST and reach maximum totality at around 10:32pm PST wherein the entire eclipsed Moon will be bright red in color. During this time, the winter constellations will be well placed for viewing so a number of bright stars can be used for magnitude comparisons. Aldebaran (mv = +0.87) is 9° to the southwest of the eclipsed Moon, while Betelgeuse (mv = +0.45) is 19° to the southeast, Pollux (mv = +1.16) is 37° east, and Capella (mv = +0.08) is 24° north.

Afterwards, the Moon will start to exit totality phase little by little at around 10:57pm PST until it exits the umbral phase entirely at around 12:18 am of December 11, 2011. and finally, the Moon will exiting the penumbral phase from the western part of the Moon at around 1:30am PST.

The full detail of the eclipse circumstances as well as diagram ( http://www.astroleaguephils.org/111210tle_espenak.pdf ) courtesy of Fred Espenak are as follows:

Eclipse Phases Time (PST) Altitude Azimuth
Moon enters Penumbra 07:33:32 pm 30 deg 72 deg E
Moon enters Umbra 08:45:42 pm 47 deg 72 deg E
Moon enters Totality 10:06:16 pm 64 deg 67 deg E
Maximum Totality 10:31:48 pm 70 deg 63 deg NE
Moon exits Totality 10:57:24 pm 75 deg 55 deg NE
Moon exits Umbra 12:17:58 am 80 deg 325 deg NW
Moon exits Penumbra 01:30:00 am 65 deg 294 deg NW

Members of the Astronomical League of the Philippines will be observing and documenting this event at AstroCamp Observatory . For more inquiries on the eclipse as well as our setup times , kindly contact ALP President James Kevin Ty at 09178559863 or ALP PRO Armando Lee at 09177922053.