They can't be flying above or below earth, or it would tend to use the "assist energy" to speed the spacecraft outside of the ecliptic. That would waste energy needed to speed/increase-solar-orbital-radius of the spacecraft.

That means that it must be passing by earth, when it is winter in the south and the earth is tilting away (northern hemispheric bigotry, here) from the spacecraft. If the spacecraft manages to pass on the solstice, then it would pass directly over the Tropic of Capricorn - 23.5 degrees off the equator. Any other appearance of right-over-the-pole must be optical illusion.

So the big question is why is it extreme winter in the south when these probes pass by. Question: were they both headed for mars as their next stops?