The Mars Opposition – Part 1 – It is Coming!

Mid-summer of 2018 will be a very good time to observe Mars.  During this period, the Mars-Earth distance will be at its lowest in 15 years.  These opportunities come rarely because of the shape of the orbit of Mars.

Here is a diagram of Earth’s and Mars’ orbits, drawn to scale (thanks to the SkySafari app):7-26-18.jpg d

As you can see, Earth’s orbit is a lot rounder than Mars’ orbit.  As the two planets progress around the Sun their oppositions (closest alignments) can be close or distant.  Oppositions occur approximately every 26 months.  For clarity, we are showing only two oppositions, a  close one (this July) and a distant one (in 2027).

At the next opposition, which occurs on July 26, 2018, Mars will be at its brightest.  This will also be the best time use a telescope to look at its surface features. Of course, weather and other things get in the way, so it would be good to start looking before opposition and continue to look for opportunities after opposition.

Here is a lengthy article, which I haven’t read:

Figure 4 is the item of interest.  This is an illustration of the relative sizes of Mars as it would appear before and after opposition.  It highlights the importance of viewing during the closest Earth-Mars encounter.  Late July is very good; late October is not good at all.  (The surface detail of these images is much better than we would expect to see, even with a very good telescope.)

For those in the Northern hemisphere, frostbite will not be an issue.  However, the time to view Mars will be a bit inconvenient.  Mars won’t rise until after midnight and won’t reach its highest elevation on the sky for another 2 hours.  Mars will be low in the sky, so our view will be distorted by a lot of turbulent air.  In the Southern hemisphere, Mars will rise early and be very high in the sky by mid-evening.

On and around July 26, 2018, Mars will be impressive naked-eye or with a small telescope.  To make the best use of this opportunity, a large telescope will enable the best look at the surface features.  There are many observatories which have public viewing nights.  There are also many star parties hosted by astronomy clubs.  Or maybe you know someone who has a large telescope, and is waiting for someone to ask…

Upcoming posts will cover this topic in more detail.

lookin’ up,



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