Mars at solar conjunction

2019 Sep 2

Mars 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, Mars 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, Mars will also be at its most distant from the Earth – receding to a distance of 2.67 AU – since the two planets will lie on opposite sides of the solar system.

If Mars could be observed at this time, it would appear at its smallest and faintest on account of its large distance. It would measure 3.5 arcsec in diameter.

Over following weeks and months, Mars will re-emerge to the west of the Sun, gradually becoming visible for ever-longer periods in the pre-dawn sky. After around a year, it will reach opposition, when it will be visible for virtually the whole night. A chart of the path of Mars across the sky in 2019 can be found here, and a chart of its rising and setting times here.

The position of Mars at the moment it passes solar conjunction will be:

Object Right Ascension Declination Constellation Angular Size
Mars 10h45m30s +09°02' Leo 3.5"
Sun 10h44m +08°01' Leo 31'41"

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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