The total lunar eclipse tonight will mark the beginning of winter solstice for the first time on over 400 years.
The last time these two events occurred simultaneously was in 1638.
Viewers in North America will see the eclipse begin around 1:32 am EST. Totality will occur from 2:41 am to 3:53 am EST. During this phase the moon will show as a rusty orange-red color.
This event will mark the start of winter solstice 2010. The shortest day of the year has fallen previously on December 21 but never with the lunar eclipse. It has been centuries since the two events coincided.
The next time this will occur will be in 84 years. While not as long as this last wait, it will still be far beyond the lifetime of most who will witness it tonight.