How Neptune’s apparent size changes
Neptune appears 2.4″ across on 22 October 2026. It is 28.982 AU from Earth and is currently close to its largest apparent size in this cycle.
Neptune Size and Distance
Drag through the orbit to see how Neptune’s apparent size, distance, brightness and illumination change over time.
- Angular diameter
- 2.4″
- Distance to Earth
- 28.982 AU
- Magnitude
- 7.7
- Illuminated
- 100%
Drag the orbit to move through the cycle
Neptune Apparent Size Over Time
Approximately weekly samples cover the complete minimum–maximum–minimum cycle. Exact event dates are inserted between sampled rows.
| Date | Angular size | Distance | Magnitude | Rise–Set | Best observing |
|---|---|---|---|---|---|
| Minimum | 2.2″ | 30.879 AU | 7.8 | 05:07 – 17:08 | — |
| 2.2″ | 30.871 AU | 7.8 | 04:41 – 16:41 | — | |
| 2.2″ | 30.849 AU | 7.8 | 04:14 – 16:14 | — | |
| 2.2″ | 30.814 AU | 7.8 | 03:48 – 15:47 | — | |
| 2.2″ | 30.765 AU | 7.8 | 03:22 – 15:20 | — | |
| 2.2″ | 30.705 AU | 7.8 | 02:55 – 14:53 | — | |
| 2.2″ | 30.634 AU | 7.8 | 02:28 – 14:27 | 02:49 – 03:02 | |
| 2.2″ | 30.552 AU | 7.8 | 02:01 – 14:00 | 02:22 – 02:54 | |
| 2.2″ | 30.46 AU | 7.8 | 01:34 – 13:34 | 01:55 – 02:47 | |
| 2.2″ | 30.361 AU | 7.8 | 01:07 – 13:07 | 01:28 – 02:41 | |
| 2.3″ | 30.256 AU | 7.8 | 00:40 – 12:40 | 01:01 – 02:37 | |
| 2.3″ | 30.145 AU | 7.8 | 00:13 – 12:13 | 00:34 – 02:35 | |
| 2.3″ | 30.03 AU | 7.8 | 23:45 – 11:46 | 00:06 – 02:35 | |
| 2.3″ | 29.913 AU | 7.8 | 23:18 – 11:19 | 23:39 – 02:36 | |
| 2.3″ | 29.795 AU | 7.8 | 22:51 – 10:52 | 23:12 – 02:39 | |
| 2.3″ | 29.678 AU | 7.8 | 22:23 – 10:24 | 22:44 – 02:43 | |
| 2.3″ | 29.564 AU | 7.7 | 21:56 – 09:57 | 22:17 – 02:49 | |
| 2.3″ | 29.453 AU | 7.7 | 21:28 – 09:29 | 21:49 – 02:55 | |
| 2.3″ | 29.349 AU | 7.7 | 21:00 – 09:01 | 21:21 – 03:02 | |
| 2.3″ | 29.252 AU | 7.7 | 20:33 – 08:33 | 20:54 – 03:09 | |
| 2.3″ | 29.163 AU | 7.7 | 20:05 – 08:05 | 20:26 – 03:17 | |
| 2.3″ | 29.084 AU | 7.7 | 19:37 – 07:37 | 19:58 – 03:24 | |
| 2.4″ | 29.017 AU | 7.7 | 19:09 – 07:09 | 19:30 – 03:31 | |
| 2.4″ | 28.962 AU | 7.7 | 18:41 – 06:40 | 19:02 – 03:38 | |
| 2.4″ | 28.919 AU | 7.7 | 18:13 – 06:12 | 18:34 – 03:45 | |
| 2.4″ | 28.891 AU | 7.7 | 17:41 – 05:39 | 18:11 – 03:51 | |
| 2.4″ | 28.877 AU | 7.7 | 17:13 – 05:11 | 18:00 – 03:57 | |
| Maximum | 2.4″ | 28.876 AU | 7.7 | 17:09 – 05:07 | 18:01 – 03:56 |
| 2.4″ | 28.878 AU | 7.7 | 16:44 – 04:43 | 17:49 – 04:03 | |
| 2.4″ | 28.893 AU | 7.7 | 16:16 – 04:15 | 17:39 – 03:50 | |
| 2.4″ | 28.923 AU | 7.7 | 15:48 – 03:47 | 17:29 – 03:22 | |
| 2.4″ | 28.967 AU | 7.7 | 15:19 – 03:19 | 17:20 – 02:54 | |
| Today | 2.4″ | 28.982 AU | 7.7 | 15:11 – 03:11 | 17:17 – 02:46 |
| 2.4″ | 29.025 AU | 7.7 | 14:51 – 02:52 | 17:12 – 02:26 | |
| 2.3″ | 29.095 AU | 7.7 | 14:23 – 02:24 | 17:05 – 01:59 | |
| 2.3″ | 29.177 AU | 7.7 | 13:55 – 01:56 | 16:59 – 01:31 | |
| 2.3″ | 29.27 AU | 7.7 | 13:26 – 01:28 | 16:55 – 01:03 | |
| 2.3″ | 29.371 AU | 7.7 | 12:59 – 01:00 | 16:52 – 00:35 | |
| 2.3″ | 29.48 AU | 7.7 | 12:31 – 00:33 | 16:50 – 00:07 | |
| 2.3″ | 29.595 AU | 7.7 | 12:03 – 00:05 | 16:51 – 23:40 | |
| 2.3″ | 29.713 AU | 7.7 | 11:35 – 23:37 | 16:52 – 23:12 | |
| 2.3″ | 29.834 AU | 7.8 | 11:08 – 23:10 | 16:55 – 22:45 | |
| 2.3″ | 29.956 AU | 7.8 | 10:41 – 22:42 | 17:00 – 22:17 | |
| 2.3″ | 30.075 AU | 7.8 | 10:14 – 22:15 | 17:05 – 21:50 | |
| 2.3″ | 30.192 AU | 7.8 | 09:47 – 21:48 | 17:11 – 21:23 | |
| 2.3″ | 30.304 AU | 7.8 | 09:20 – 21:21 | 17:17 – 20:56 | |
| 2.2″ | 30.409 AU | 7.8 | 08:53 – 20:54 | 17:24 – 20:28 | |
| 2.2″ | 30.506 AU | 7.8 | 08:26 – 20:26 | 17:31 – 20:01 | |
| 2.2″ | 30.594 AU | 7.8 | 08:00 – 19:59 | 17:38 – 19:34 | |
| 2.2″ | 30.671 AU | 7.8 | 07:33 – 19:32 | 17:45 – 19:07 | |
| 2.2″ | 30.737 AU | 7.8 | 07:07 – 19:05 | 17:51 – 18:40 | |
| 2.2″ | 30.79 AU | 7.8 | 06:40 – 18:39 | 17:58 – 18:14 | |
| 2.2″ | 30.83 AU | 7.8 | 06:13 – 18:13 | — | |
| 2.2″ | 30.857 AU | 7.8 | 05:47 – 17:46 | — | |
| 2.2″ | 30.87 AU | 7.8 | 05:20 – 17:20 | — | |
| 2.2″ | 30.871 AU | 7.8 | 05:16 – 17:16 | — | |
Why Does Neptune Change Size?
Neptune’s physical diameter is not changing. Its apparent angular diameter changes mainly because the distance between Earth and Neptune changes as both planets move around the Sun.
When Will Neptune Have Its Largest Apparent Diameter?
Neptune reached an apparent diameter of 2.4″ on 23 September 2026. That is about 1× wider than today, or roughly 1× the apparent disk area.
The largest apparent-size date has an observing interval from your location: 18:01 – 03:56. Apparent size alone does not describe seeing or atmospheric conditions.