Portal:Astronomy/Events/December 2009
| 2 December, 07:32 | Full moon | 
| 4 December, 14:00 | Moon at perigee | 
| 14 December | Geminids peak | 
| 16 December, 12:03 | New moon | 
| 18 December, 17:00 | Mercury at greatest eastern elongation | 
| 20 December, 15:00 | Moon at apogee | 
| 21 December, 17:48 | Earth southern solstice | 
| 22 December | Ursids peak | 
| 31 December, 19:23 | Full moon and partial lunar eclipse |