Less than a week after astronaut Neil Armstrong’s passing, there's a rare 'blue moon' on Friday’s cosmic calendar.
That's the day of a private service for Armstrong, the first man to walk on the moon, who died last Saturday in Ohio at age 82.
A blue moon occurs when there's a second full moon in one calendar month. It won't happen again until July 2015. The full moon cycle is 29.5 days so a blue moon is uncommon and has come to mean something rare. The moon actually won't be colored blue.
Armstrong's family has suggested paying tribute to him during Friday’s Blue Moon.
