Thanks to the relative closeness of Mars when at opposition we can observe its surface details even in small telescopes. But what exactly are we able to see? It turns out that even in a 5 centimeter instrument (it's only 2''!) under good seeing one can glimpse the polar cap! In a bigger telescope with a diameter of at least 15 centimeters (6'' – in Poland this apperture is very popular) we can also see some surface details... It is also good to use a color photographic filter.

A red filter enhances the contrast between bright and dark areas bringing out a lot of details usually dimmed by the glare of the planet. A blue filter makes it easier to see the polar cap and clouds (especially close to the edge ot the disk). If such filter is not availible you can use a once very popular item... 3D glasses (the author of this webpage has had an opportunity to test such glasses in person!). Of course we cannot see a 3D Mars through them (although we really wish to!) mainly because we use only one eye at the telescope although the glasses do have a red foil for one eye and blue for the other! Anyway Mars is worth looking at for instance to see white clouds over huge volcanoes ofi Tharsis and Elysium, the canal of Coprates, a sand desert called Syrtis Major and many others...

    Another interesting feature of Mars is that it encircles the Sun in an orbit relatively close to the Earth (for an outer planet) so sometimes we are able to see a part of the side not illuminated by the Sun with a phase of up to 85%!

    The main contributors in getting to know Mars better are the space probes. A lot of them have been sent to the Red Planet but they were mostly lost. Those which survived have proven that there is no life on Mars. In spite of that it is still a very INTERESTING planet! It has very similar geological features like the Earth e.g. volcanoes (probably not active any more) and also canyons. However compared to their terrestrial counterparts, these are really huge! Olympus Mons is a good example being the largest volcano in the Solar System with a surface comparable to the surface of Poland (about 600 kilometers) and a height of 21.3 kilometers! The Valles Marineris (corresponding to an albedo feature called Coprates), is a few kilometers deep and has a length of about 4000 kilometers. It takes up one fifth of the planet's equator and is comparable in its span to the whole continent of Asia on Earth (therefore dwarfing the Grand Canyon in Colorado which is over ten times smaller!).

    Long term exploration of Mars surface has revealed that it consists mainly of ferrum oxides (also called simply rust) and that's what gives it a reddish hue! The atmosphere of Mars is very thin consisting mainly of carbon dioxide. Sometimes there are large dust storms, which may even cover up the entire planet! The surface pressure is almost 150 times smaller than on Earth (corresponding to the terrestrial surface pressure at an altitude of about 50 kilometers!). This is why Mars cannot support liquid water on its surface since with such a low surface pressure it would sublimate in an instant! The surface temperatures range between –87 degrees centigrade (186 K) and –5 degrees centigrade (268 K) causing the polar caps to consist mainly of frozen carbon dioxide. Since Mars' axis is similarily tilted like the Earth's it exhibits similar seasons although they last twice as long as the terrestrial ones. When a warmer season begins on a given hemisphere its polar cap is shrinking rapidly and that on the opposite side is growing larger. With the rise of temperature the frozen carbon dioxide sublimes which means that it goes directly into the gaseous phase.
    Presumably as early as 2 to 3 billion years ago Mars had a dense atmosphere and a reservoirs of liquid water since space probes have sent us photos of unusual and mysterious surface features resembling dry river beds...