What is the opposition of Mars, and why it is so important for astronomers – BBC

Today, 22 May, began regular opposition of Mars – the event, when the Sun, Earth and Mars during its orbital motion are arranged in almost a straight line. At a minimum the Earth distance of Mars will approach later – it will happen on May 31 in 1.00 Moscow time

In fact, at this time Mars will be from the Earth at a distance of 75 million km. is two times closer than the sun

The Earth and Mars -. planets neighbors. The orbit of Mars is on earth, so that one turn he performs in nearly two years – 686.98 Earth days. Earth moving faster in its orbit, first overtakes a slower Mars, but soon, making a full turn, again finds himself in the role of pursuer. Thus, the opposition of Mars, repeated every 26 months. Astronomers are waiting these events, because in times of confrontation, when Mars is closer to Earth, its surface is easier to learn a telescope

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oppositions of Mars are important for space missions. For reasons of economy start window interplanetary spacecraft to Mars is chosen so that the distance between the planets as small as possible. Therefore, usually the start is carried out a few months before another confrontation – and then the flight time, and fuel consumption will be minimal

By the way, recently it for this design, the first spacecraft series was launched. “exomars”, whose task is to search for traces of past and present life on Mars.

If Earth and Mars orbits were circular, then all opposition would be exactly the same. However, in contrast to the Earth’s orbit, which, though stretched, but just a little bit, the orbit of Mars is quite elongated ellipse. Distance between Mars and the Sun varies from 206.6 to 249.2 million km. Revolving around the Sun each time a planet found in different places of their orbits, coming closer with each other at different distances. By the way, precisely because of the elongation of the orbits of the moment of confrontation is not the same a little bit with the time of closest approach of the planets. Such convergence, when the planet Mars is at perihelion of its orbit, called the great confrontations. They occur every 15-17 years, usually in the summer or early autumn.

It is with great opposition for a long time been associated high-profile opening in the history of the study of Mars.

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The most famous opposition of Mars occurred in early September 1877. Then the American astronomer Asaph Hall discovered two small Martian satellites – Phobos and Demos. At the same time, the Italian astronomer Giovanni Schiaparelli discovered on Mars Strange straight lines, which are called “channels.” Despite the fact that he did not think Schiaparelli channels artificial constructions discovered them, many of his contemporaries this discovery convinced of the existence of advanced Martian civilization. The enthusiasm lasted many decades, giving rise to such famous literary novels about Mars as the “War of the Worlds” by HG Wells or “Aelita” Alexei Tolstoy

The current opposition of Mars -. The last before the great opposition in 2018.

On May 28 the Red Planet will be in the constellation of Libra, and from mid-latitudes to observe it will be virtually overnight. However, its height above the horizon does not exceed 15 degrees, which imposes certain restrictions on the ability to carry out surveillance of the major cities, as the skyline is often not visible because of dense development. On Mars, the sky will look like a bright red star flicker-free -. 2.1 magnitude, which is only slightly less than the brightness of the night sky of the planet Jupiter

At the time of closest approach of the apparent diameter of the Red Planet will be 18.6 arcsec . This makes it possible to distinguish between small disk of the planet, even in a small telescope or binoculars. However, in order to discern details on the planet’s surface, such as the polar caps and the dark areas of the surface, you need to use a larger telescope with a diameter of 100 mm. Experienced amateur astronomers advised to use when observing Mars orange and yellow filters. They emphasize quality surface detail and make the picture sharper.