Portal:Astronomy/Events/October 2021
| 6 October, 11:05 | New moon |
| 8 October, 03:50 | Mars at conjunction |
| 8 October, 17:28 | Moon at perigee |
| 9 October, 16:12 | Mercury at inferior conjunction |
| 20 October, 14:57 | Full moon |
| 21 October, 11:30 | Peak of Orionids meteor shower |
| 24 October, 15:30 | Moon at apogee |
| 25 October, 04:59 | Mercury at greatest western elongation |
| 29 October, 21:59 | Venus at greatest eastern elongation |