by William J. Bechaver
Alas, our chance to view amazing Mars close up is here!
This week, on Thursday 26 July, Mars will be at opposition, the position in the sky when the red planet is directly opposite from the Sun!
So, right when the Sun is setting in the west, Mars will be rising in the east. The event actually occurs shortly after midnight that night, in the early morning hours of Friday.
The orbits of Earth and Mars around the Sun are elliptical, meaning that sometimes the orbits of the two planets come closer to each other than at other passes. This year’s opposition causes the Earth to come closer to Mars than during previous passes. So the time to view Mars at its closest is now.
However, due to that ellipticity of their orbits, even though at opposition on Friday, the day when the two should be closest together, that event doesn’t occur until a few days later. Even though we are past Mars on Friday, the orbit of Mars will cause the planet to come a little closer to Earth a few days later, on the night of Monday 30 July. On that night, Mars will be only about a hundred thousand miles closer to Earth, a distance that is certainly not observable from here.
However, when we started watching Mars a couple of months ago, it was an impressive 72 million miles distant. Now in the short span of about nine weeks, we have closed the gap, and will be less than half the distance, being only 35.7 million miles away!
The viewing opportunities for Mars will actually improve during the next couple of weeks, as we pass it, and it begins to rise earlier every night, bringing it high into the sky during the early evening hours for prime viewing.
This is a wonderful opportunity to view Mars at its closest. After this weekend, the race is won, and Earth will pass Mars. We won’t catch up to it again until mid October in the year 2020! And then, our orbits being situated as they are, we will be a full 3 million miles more distant from the red planet on our next closest approach, so this is our chance to view Mars at its closest.
The other big event of July 27 will be the total lunar eclipse. An eclipse of the Moon occurs when the Earth passes between the Sun and casts it’s shadow on the surface of our satellite.
This year’s event has been touted at the longest for the duration of totality this century! But, even so, we can not view even a moment of it from mainland America. The entire event will occur when it is night and the Moon is high in the sky on the other side of the planet, during our daylight hours.
But this does afford us another viewing opportunity, even though we will completely miss out on the total lunar eclipse. Mars and the Moon both being essentially at opposition on the same night, the full Moon will join brilliant Mars in the sky on Thursday night, coming closest to the red jewel in the sky just before dawn on Friday morning. So, anytime during the night, go out and look for Mars riding with the full Moon across the sky!
And, for a total lunar eclipse, we in the Americas will only have to wait until January, when the next total lunar eclipse will occur.
Thanks for your continued interest in our astronomy columns. If you have any questions or article requests, contact us at email@example.com, or follow us on Twitter @ColoSpacEScapE for updates and additional viewing opportunities, and upcoming Mars viewing dates!
• · William J. Bechaver is the director of SPACE • Spanish Peaks Amateur Cosmos Enthusiasts, the premier Astronomical Society for Southern Colorado and Northern New Mexico.