© NASA/Voyager 2

Neptune at solar conjunction

Dominic Ford, Editor
From the Outer Planets feed

Objects: Neptune
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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
Neptune 23h26m10s -04°48' Aquarius 2.2"
Sun 23h24m -03°49' Aquarius 32'12"

The coordinates above are given in J2000.0.

The sky on 10 March 2021
Twilight ends
Twilight begins

27-day old moon
Waning Crescent


27 days old

Rise Culm. Set
Mercury 05:47 11:04 16:21
Venus 06:49 12:32 18:14
Moon 05:50 10:49 15:48
Mars 10:09 17:25 00:42
Jupiter 05:31 10:45 15:58
Saturn 05:03 10:07 15:12
All times shown in MST.


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 DE430 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.

Related news

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

Image credit

© NASA/Voyager 2






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