Neptune will pass very close to the Sun in the sky as its orbit carries it around the far side of the solar system from the Earth.
At closest approach, Neptune will appear at a separation of only 1°04' from the Sun, making it totally unobservable for several weeks while it is lost in the Sun's glare.
At around the same time, Neptune will also be at its most distant from the Earth – receding to a distance of 30.92 AU – since the two planets will lie on opposite sides of the solar system.
If Neptune could be observed at this time, it would appear at its smallest and faintest on account of its large distance. It would measure 2.2 arcsec in diameter.
Over following weeks and months, Neptune will re-emerge to the west of the Sun, gradually becoming visible for ever-longer periods in the pre-dawn sky. After around six months, it will reach opposition, when it will be visible for virtually the whole night. A chart of the path of Neptune across the sky in 2021 can be found here, and a chart of its rising and setting times here.
The position of Neptune at the moment it passes solar conjunction will be:
|Object||Right Ascension||Declination||Constellation||Angular Size|
The coordinates above are given in J2000.0.
|The sky on 10 March 2021|
27 days old
All times shown in EST.
Never attempt to point a pair of binoculars or a telescope at an object close to the Sun. Doing so may result in immediate and permanent blindness.
The circumstances of this event were computed using the DE405 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).
This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.
|10 Mar 2021||– Neptune at solar conjunction|
|14 Sep 2021||– Neptune at opposition|
|13 Mar 2022||– Neptune at solar conjunction|
|16 Sep 2022||– Neptune at opposition|