Both a blue moon and a lunar eclipse occur.

Blue moon

Name for three (unconnected) events

A blue moon refers either to the presence of a second full moon in a calendar month, to the third full moon in a season containing four, or to a moon that appears blue due to atmospheric effects.

December 2009 lunar eclipse

A partial lunar eclipse occurred at the Moon’s descending node of orbit on Thursday, December 31, 2009, with an umbral magnitude of 0.0779. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A partial lunar eclipse occurs when…