My Dark Sky

How do you plan to celebrate the beginning of a new decade? How ‘bout doing it the Moon’s way… by moving into the Earth’s shadow?

On the last day of this decade (depending on where you are… on my side of the globe it’s already a new year), our Moon will pass through the Earth’s umbra shadow ever so slightly that you may not even notice it.

As usual, check out shadow and substance for a nice animation

This partial lunar eclipse will start on Dec 31, 17:17 UT (1:17 am, Jan 1 Malaysia Time) when the Moon touches the Earth’s penumbra shadow. About 1.5 hours later, the Moon reaches the umbra shadow. It takes another hour to cruise through the umbra and finally leaves the penumbra at 21:28 UT (5:28 am Malaysia Time).

At maximum eclipse (3:23 am), less than 10% of the Moon will be in the umbra shadow, only a very tiny bit of the Moon will be “eaten” – unaware observer may just think that the Moon isn’t full on that day. Most part of the Moon will be in the penumbra – which is the lighter part of Earth’s shadow – so the Moon will only be slightly dimmed, which may not be obvious.

You can see this eclipse just outside your house or any place where you can see the Moon during this time. No special equipment is needed, your naked eyes alone is enough. Alternatively you can also see it through binoculars or telescope (no filter required). Or you can setup your camera to record the event.

I think it’s also worth mentioning that this full moon is also a “blue moon”. Usually, we will have one full moon per month, but when a month has two full moons, the second one is called the blue moon, it’s not that you will see the Moon turns blue. Blue moons are rare (that’s how we have the expression “once in a blue moon”), it’s only happens every 2 – 3 years, and the next one will be in August 31, 2012.

Enjoy the show and clear skies to everyone out there.

Always look up, and you will be rewarded with the beauty of the night sky…

~ by thChieh on December 28, 2009.

Posted in Observations & Tips
Tags: Lunar eclipse