Don’t miss 2010’s solstice lunar eclipse tonight!

There is a lunar eclipse on December 21. This December solstice eclipse is also the northernmost total lunar eclipse for several centuries.

There won’t be a total lunar eclipse this far north on the sky’s dome until December 21, 2485.

That’s because this eclipse is happening almost simultaneously with the December solstice – which in 2010 occurs on December 21 – when the sun will be southernmost for this year. Remember, a totally eclipsed full moon has to lie exactly opposite the sun. The winter sun rides low to the south now, as it crosses the sky each day. So this December full moon is far to the north on the sky’s dome. It rides high in the sky – much like the June solstice sun.

Remember, it’s the same eclipse – happening in the same magical moments – for all of us.

A total lunar eclipse takes place whenever the moon passes right through the Earth’s dark umbral shadow. This can only happen at full moon, which is when the moon has swung directly opposite the sun in our sky, in its monthly orbit of Earth. During tonight’s total lunar eclipse, the moon will be totally immersed in Earth’s shadow for 72 minutes. A partial eclipse lasting for nearly the same period of time will precede and follow the total eclipse. The entire eclipse from start to finish will last about 3.5 hours.

www.earthsky.org