Neptune
Neptune Sky Charts and Coordinates
This is a simplified sky chart, showing where Neptune is now with respect to the brightest stars and constellations.
More advanced sky charts are available on TheSkyLive for this object: 1) the Online Planetarium which is interactive and allows to select dates and additional objects to visualize; and 2) the Live Position and Data Tracker which provides the highest precision position data and features deep sky imagery from the Digitized Sky Survey.
High Precision Live Sky Chart
Neptune Rise and Set Times
Today's Neptune rise, transit and set times from Greenwich, United Kingdom [change]. All times are relative to the Europe/London timezone.
Neptune Ephemeris
The following table lists the ephemerides of Neptune computed for the past and next 7 days, with a 24 hours interval. Click on each row of the table to locate Neptune in our Online Planetarium at the chosen date.
| Date | Right AscensionR.A. | DeclinationDec. | MagnitudeMag | Apparent DiameterDiameter | Constellation |
|---|---|---|---|---|---|
| 2018 Dec 08 | 23h 00m 37s | -07° 23’ 49” | 7.89 | 2.3” | Aquarius |
| 2018 Dec 09 | 23h 00m 38s | -07° 23’ 38” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 10 | 23h 00m 41s | -07° 23’ 25” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 11 | 23h 00m 42s | -07° 23’ 12” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 12 | 23h 00m 44s | -07° 22’ 57” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 13 | 23h 00m 47s | -07° 22’ 41” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 14 | 23h 00m 50s | -07° 22’ 26” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 15 | 23h 00m 51s | -07° 22’ 09” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 16 | 23h 00m 55s | -07° 21’ 51” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 17 | 23h 00m 56s | -07° 21’ 33” | 7.90 | 2.3” | Aquarius |
| 2018 Dec 18 | 23h 01m 00s | -07° 21’ 14” | 7.91 | 2.3” | Aquarius |
| 2018 Dec 19 | 23h 01m 02s | -07° 20’ 53” | 7.91 | 2.3” | Aquarius |
| 2018 Dec 20 | 23h 01m 05s | -07° 20’ 33” | 7.91 | 2.3” | Aquarius |
| 2018 Dec 21 | 23h 01m 09s | -07° 20’ 12” | 7.91 | 2.2” | Aquarius |
Distance of Neptune from Earth
The following chart shows the distance of Neptune from Earth as a function of time. Distance data is measured in Astronomical Units and sampled with a 2 days interval.
The reported distances might be inaccurate around the times of closest approach for objects passing extremely close to Earth. The value of the distance of Neptune is also available as a real time updated value in the Live Position and Data Tracker.
Light Curve of Neptune
The following chart is the predicted light curve (visual magnitude as a function of time) of Neptune, according to the most recent ephemerides data. Magnitude data is sampled with a 2 days interval and there might be inaccuracies for objects changing brightness very rapidly during the course of a few days. For comets there could be large discrepancies between the observed and predicted brightness because of their highly dynamic behaviour.
Neptune Physical Data
The following shows the known values of the most important physical parameters of Neptune. Source: JPL Small-Body Database
| Physical Parameter | Value | Relative to Earth |
|---|---|---|
| Diameter | 49244 km | 3.8647 |
| Mass | 102.41 x 1024 kg | 17.1478 |
| Density | 1.638 gr/cm3 | 0.2971 |
| Escape Velocity | 23.56 km/s | 2.1055 |
| Sideral Rotation | 16.1100 hours | 0.6731 |
| Absolute Magnitude | -6.87 | |
| Geometric Albedo | 0.41 | |