Mars at solar conjunction

2017 Jul 27

Dominic Ford – originally published on In-The-Sky.org

From our vantage point on the Earth, Mars will appear very close to the Sun in the sky as it passes around the far side of the solar system from the Earth.

At closest approach, Mars and the Sun will appear at a separation of only 1°06', making Mars 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 2.66 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 night sky 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 08h26m10s +20°19' Cancer 3.5"
Sun 08h25m +19°15' Cancer 31'29"

The coordinates above are given in J2000.0.


The details of this observing event were provided courtesy of In-The-Sky.org

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