Six Months to Mars

The morning sky is getting colder – but Mars out there has reached a cold extreme.

Planets in the morning sky

The planets stay near the ecliptic; the other line, with the motion-arrow on it, is the celestial equator. The shapes of a few prominent constellations – Corona Borealis, Boötes, and Corvus – are included to give an idea of where we are in the sky, though their fainter stars may not be discernible in the twilight.

Mars is at aphelion, its farthest point from the Sun in its 1.88-year orbit.

Spce diagram, Earth sightline to Mars

Here are the planets’ courses in November and December, with stalks connecting them to the ecliptic plane, and the Earth-Mars sightline of Nov. 21. The ram’s-head symbol represents the vernal equinox direction, the zero-point for celestial mapping.

You can see that we are on the way to overtake Mars – and that this implies seeing it to the “right” (west) of the Sun. We are on the inside track and moving faster, yet it will take us till next May 22 to catch up and pass between Mars and the Sun – in other words, that’s when it will be at opposition.


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