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 |