Portal:Astronomy/Events/September 2018
| 7 September | Neptune at opposition |
| 7 September | Comet 21P/Giacobini–Zinner at brightest |
| 8 September, 01:13 | Moon at perigee |
| 8 September, 22:16 | Moon occults Mercury |
| 9 September, 18:02 | New moon |
| 20 September, 00:48 | Moon at apogee |
| 21 September, 01:54 | Mercury at superior conjunction |
| 23 September, 01:54 | Earth at southward equinox |
| 25 September, 02:52 | Full moon |