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It has been built since the beginning of spring and culminates at the end of this month – the big Mars show of 2018.
The Earth and Mars have their closest approach in 15 years. In 2003, Mars and Earth were separated by only 34,646,418 miles, and although it was a fairly large distance, it was the closest that the two planets came together for nearly 60,000 years. In the early hours of July 31, Mars will be only 35,785,537 miles from Earth, less than 1.2 million miles more than in 2003.
To all practical applications, Mars will be as big and brilliant as it was at the time. With the exception of Venus, who lies down in the west sky in the early evening, Mars will be the brightest star-shaped object in all of the sky until the evening. at the beginning of September. If you ever needed an excuse to buy a telescope, that's it! Mars will not be as close before 2035.
To add to this week's show, the full moon will be in a heavenly hug with Mars as it gets up Thursday and Friday night. On Thursday night, the moon will be just above and to the right of Mars, and on Friday night it will be at the top left of our Martian neighbor. Do not miss this great conjunction!
Mars and Earth are in what astronomers call "opposition" this week. As you can see in the diagram, this places Mars and Earth at minimal separation. It also makes Mars available all night, getting up at sunset and going to bed at sunrise. It takes 365.25 days to Earth to make a complete orbit around the sun, while Mars takes 587 days. Because of this, Mars and Earth find themselves in opposition every two years. The Earth is roughly in a line between Mars and the sun.
However, not all oppositions are equal. Some bring Mars and Earth closer together than others. This is because the orbits of the two planets are ellipses rather than perfect circles. The orbit of Mars is a little more elliptical, or oval, than the orbit of the Earth, as you can see on the diagram; although for purposes of explanation, the ellipse is a little exaggerated.
Because of their elliptical orbits, Mars and Earth have minimum and maximum distances from the sun. In the case of Earth, the difference between our minimum and maximum distance from the sun is not as great as in the case of Mars. During the Mars-Earth opposition of 2018, the Earth is close to its greatest distance from the sun, and Mars is very close to its minimal distance, putting Mars and Earth very close to each other, as in 2003. [Photo: MikeLynch]
It's normally a wonderful time to check Mars even with a small to moderate telescope. Mars is the only planet in our solar system where you can actually see the surface. With other planets like Jupiter, Saturn and Venus all you see are clouds. I certainly do not want to overload what you will see on Mars, though. There remains only a planet of 4,000 miles wide at nearly 36 million kilometers. Even with higher magnification, it will not fill the field of the eyepiece of your telescope.
However, and it is a big "however", there is bad news with this year's opposition. There is a global dust storm that darkens the red planet. At the present time, it seems that this will continue until August and perhaps even September. The storm is very similar to the one that occurred in 2001 when Mars and Earth were also close. There is a chance that the current forecast for the storm will not hold up completely and we could have a break. Let's hope so! Otherwise, everything you see on Mars, through a telescope of any size, will be a big orange disk and that's about it.
If the storm soothes and you see Mars, here are some tips. To have the best views of Mars on the telescope, you will want to stay awake late at night if you try to take a look around mid-August. Even without a dust storm, if you point your reach at Mars when she starts to get up, you will have a very fuzzy and distorted view because of the thicker layer of blurry atmosphere of the Earth near you. ;horizon. It is best to wait until midnight, and even better if you wait until 1 am, when the planet is at its maximum height in the sky above the southern horizon.
Unfortunately, because of Mars on a background of stars and our latitude in Minnesota and in western Wisconsin, even at its maximum altitude, will be less than one third of the distance between the horizon and the zenith. At this low altitude, there will always be at least some blur effects. High humidity will also cloud the view. Ideally, to have a better view and have Mars higher in the sky, travel to the south of the United States or even further south where you will generally have more transparent views.
It's still possible to have beautiful views of Mars through a telescope around here – if the Martian dust settles, especially from midnight to 2 am. It is important to be patient, to be in a comfortable position when you look in your field and take long continuous views of Mars, at least five to 10 minutes at a time. This will give your eyes a chance to adjust to the level of light in the eyepiece field and enjoy less turbulent and more transparent openings in the atmosphere.
Depending on the quality of the viewing, you should be able to see the south of Mars. polar cap, which is composed mainly of frozen carbon dioxide. If your telescope shows you an inverted image, as most do, the southern polar cap will be toward the upper limb or disc of the planet. With larger telescopes, and even small to medium ones, you can see dark spots on Mars. They are rocky fields, plains and vast canyons on the surface. There is even a gigantic sleeping volcano called Olympus Mons. Since Mars turns on its axis every 24 hours and a half, a little slower than our Earth, you'll see dark spot changes from evening to night and even over several hours of observation.
Sky and Telescope Magazine has a great tool available on their website, skyandtelecope.com. This is what is called the Mars Profiler, and with it you can find out which surface features on Mars are visible at any time on Earth. Look for it on their website.
Here's another tip on using your telescope: Make sure your telescope and all the eyepieces you use are on the outside for a good half hour to an hour. at outside temperatures. It really makes a difference.
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