Neptune at solar conjunction

2019 Mar 7

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 0°57' 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 30.93 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 2019 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 23h09m30s -06°26' Aquarius 2.2"
Sun 23h08m -05°33' Aquarius 32'14"

The coordinates above are given in J2000.0.

This entry in the observing calendar was provided by In-The-Sky.org

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