Mars & Observing the Red Planet

[Qualia]

Preface

The purpose of this post is to provoke a basic understanding of Mars which will not only help ignite further interest in the red planet but also aid planetary observations when out in the field. In this manner, I have divided the entry into two main divisions. The first deals with some of the more important features and characteristics of the red planet while the second entry deals with observing Mars.

Part One: A General Understanding of Mars

1 – General Introduction

Mars is a barren and cold planet orbiting the vast darkness of space. It is a world of undulating landscapes, jagged rocks and arid hills. It is dry, dusty and desolate; its air is thin and extremely cold. You probably wouldn’t want to live there for long. There are dust storms that can darken the skies for months and every night temperatures drop to about 140ºC below zero and the days rarely see better than 15ºC.

Since the beginning of the historical record, every major civilization has been captivated by the red planet. Ancient cultures worshiped Mars and typically understood it as foreshadowing chaos and catastrophe whilst more recent cultures have believed it could harbor life and even advance civilizations. Today, we see an old and weathered world, a place with ice caps, wind sculptured rock and dusky continents, but a world no less fascinating than those conjured by past civilizations.

The ancient Egyptians named their grandest city after the planet; Al Qahira, the Vanquisher, an old Arabic term for Mars which over time changed to Cairo. For Asian cultures, Mars was the fire star, a portent of grief and murder. The Greeks of the Polis called Mars Ares, the son of Zeus whose sons were Fear (Phobos) and Terror (Deimos) from which Mars’ own two moons have been named. The planet itself is named after the Roman God of war, hostility and unrest whose sons Romulus and Remus founded the city of Rome.

2 – Distance, Orbit and Seasons

Mar’s average distance from Earth is about 228 million kilometers, hurtling through space at around 86,500 kilometers an hour. If you drove a steady 120km an hour, the legal limit in most European countries and never stopped, you’d expect to arrive within 216 years. A Martian year is 687 Earth days long, and a Sol or Martian day lasts 24.6 Earth hours, or 39 minutes and 35 seconds longer than here on Earth.

The planet’s orbit is so eccentric – the most eccentric of any planet apart from Pluto - that there is quite a variation in surface temperatures ranging from a mild maximum of 27ºC to an unforgiving minus 140ºC. Putting this into some perspective, the lowest recorded temperatures on Antarctica, the coldest place on Earth, have been around minus 90ºC. Typically, the low albedo regions, the darker areas you see through a telescope, are warmer than the lighter northern or southern regions.

Although the Northern Star on Mars is the supergiant Deneb, Mars’ axial tilt is in fact very similar to our own which means it experiences similar cycles of seasons. However, due to its eccentric orbit they’re twice as long as on Earth.

Breaking down the seasons into their respective hemispheres, we end up with the following durations:

• Southern Hemisphere                  Northern Hemisphere                                                 Duration
• Spring                                                Autumn                                                                146 days.
• Summer                                             Winter                                                                  160 days.
• Autumn                                              Spring                                                                  199 days.
• Winter                                                Summer                                                               182 days.

3 - Mass, Volume and Atmosphere

In one respect Mars is similar to the Moon in that one side is heavily cratered while the other is not. It is also similar to Earth in that it has seasons, an atmosphere of sorts, and weather. There are clouds here and winds and evidence that rivers once flowed and flooded the ancient lands with water. It’s also about midway between the Earth and Moon in size, measuring around 6,800km in diameter.

In terms of volume about six Mars’ globes could fit in one Earth. Its mass is just 11% of Earth’s and it has 62% less gravitational force. This mix of low density and smaller size make things lighter on Mars. Objects fall slower, where a ton of soil would weigh about 370kg.

The gravity on Mars is just a third of Earth’s but it is still sufficient to allow the planet to retain a tenuous atmosphere. This toxic layer surrounding the red planet rises to almost 11km high, some 5km more than on Earth and consists of 95% carbon dioxide, 2.7% nitrogen, 1.6% argon and a smattering of oxygen, water, and methane.

The thin atmosphere has allowed Mars to be relentlessly attacked by space debris which would have been vaporized in our denser atmospheric veil. Like the Moon, Mars’ surface has been bombarded with impunity and its wounds and scars are evident across the entire surface.

Martian air is made up of the same stuff we have on Earth but there is death for us in it. On Earth, roughly 75% of our atmosphere is nitrogen, 23% oxygen, 1% argon and carbon dioxide makes up only 0.05%. What oxygen there was on Mars, so precious to life on Earth, has been used up, transforming the iron rich planet into a rusty oxidized red.

Considerable quantities of methane have also been found in the Martian atmosphere. A single plume can release over 40,000kg of the stuff in a single day. Methane appears to rise during the warmer spring and summer months and is distributed in large plumes over volcanic regions such as Tharsis, Elysium and Syrtis Major.

The implications of methane is interesting for on Earth it is a greenhouse gas typically released by tiny organisms present in rotting vegetation and the stomach of certain animals like sheep and cows. The existence of such a gas has sparked renewed interest in the possibility of some kind of micro life on Mars, yet we must temper this possibility with the knowledge that methane can also be produced by purely physical, non-biological processes.

4 - Retrograde Motion

In a world before electricity, people had no more than flame to light their way. Night was a blanket of darkness and Mars would have stood out more than almost any other object. In the dark, the world is not the same; the absence of light skews estimations and fires the imagination. You would see this blood red planet glaring down, distant and vaguely menacing, at times demonically possessed as it would start shifting from its forward motion and wander backwards like no other object in the night sky. Little wonder that Mars had such notorious fame. 

This phenomenon of Mars going backwards is referred to as Retrograde Motion and to get an idea of what is going on we can imagine the planets in our solar system racing around the Sun on a cosmic sized race track.  On the faster inner lanes are Mercury, Venus, Earth and Mars and on the slower outer lanes are Jupiter, Saturn, Uranus and Neptune.

From Earth’s perspective, we see Mars racing around a relatively slower outside lane and for most of the time the background stars and Mars are moving in the same direction relative to us. However, we are racing around the Sun on a faster lane, so at some point we are going to lap Mars and as we approach and then pass the red planet, for a brief period, in fact every two years as we approach Mars’ opposition, from our line of sight it actually looks like Mars is going backwards. As we draw further away from the planet after opposition, our line of sight alters the apparent course of Mars and it appears to recommence its slow eastward path.

It is so simple to explain, but in fact took thousands of years and some of the greatest minds ever to find a mechanical explanation for Mars’ bizarre orbit. In the end, it needed a radical new way of thinking, a heretical paradigm shift for which people were burnt at the stake for believing; an idea which placed the Sun at the centre of the Solar system.

5 – Regolith

The ochre hue we see of Mars is due to rusting. Over the slow march of billions of years, any oxygen there was on the planet has caused the upper layers of the Martian surface to rust and disintegrate into a dusty iron oxide.

On Mars as well as the Moon and Venus this surface material isn’t referred to as sand, soil or dirt, but regolith. The word stems from the Greek rhegos meaning blanket and lith meaning rock. As such, regolith, regardless of its material composition, is a form of very loose, ground up rock spread over the bedrock of other worlds.

Most of Mars’ regolith is a very thin, highly toxic layer of oxidized dust which is so finely ground that its particles are as fine as cigarette smoke and when winds whip up it can stay suspended for months often causing surface features to appear muted and obscure. Martian regolith creates dunes similar to those on Earth and dust devils frequently loft high into the atmosphere, whipping violently across the wind sculptured terrain. These spinning vortexes are formed when cold air drags the surrounding warmer air upwards creating huge columns of dust, some of which can rise to over 10km in height, stripping the terrain of its brighter surface dust and leaving behind dark streaks and trails.

Regolith may help shape and transform the surface of Mars but wind is the primary process of erosion as it cuts into the landscapes creating grooves, ridges and yardangs – streamlined hills carved by the wind. Mars is said to suffer from Low Thermal Inertia which means its surface heats up quite quickly in daylight. As there are no lakes or oceans to quell this effect with clouds, when the Martian land heats up, hot air rises and is replaced by cooler air. This cocktail of lower pressure air rising and a mass of cooler air racing in to replace it causes winds. Typically wind velocities on Mars are reckoned to be anything from a mild breeze to gales of around 150km an hour.

6 – Water

Traces of water vapour in the atmosphere is a 1000^th of that on Earth but even this small quantity is sufficient to form clouds and coat areas of the Martian surface in frost during the long winter chill. Mars’ low pressure prevents water molecules existing in liquid form, so when temperatures rise above freezing point, the ice and frost sublimates into vapour. From Earth the plumes of cloud, fog or ground hazes can appear as bright, transient features often covering low lying lands such as valleys and canyons and atop larger volcanic areas.

Ice and dry ice exist at the poles. Carbonates have also been found which may contain the fossilized remnants of stromatolites. Such fossilized microbes have been discovered in Australia dating back to 3.5 billion years ago, so there might be the chance of finding such microscopic Martians on Mars some day. It’s a long way from the Martians of science-fiction but even the discovery of such tiny microscopic life forms on another world produced from the wonder of amino acids would be significant, perhaps as significant as the Copernican revolution that put the Sun at the centre of the Solar System and many at the burning stake for believing such things.

7 – Core and Magnetic Field

No ghostly auroral displays grace the Martian skies and a compass here would be useless. If the existence of a magnetic field is a good indicator of a geologically active and living world, then Mars died long ago. There is no fluid molten iron at the planet’s core and any dynamo effects the planet ever had ceased billions of years ago.     

Mars’ core in now inert but evidence in rocks suggest that its original magnetic field was about a tenth of Earth’s and was lost in the late heavy bombardment period. Certainly, no impact craters after this time show signs of magnetism.

Mar’s core mass is estimated to account for 6% to 20% of the total mass of the planet and is primarily made up of nickel-iron surrounded by a silicate mantle and then a rocky crust similar to the basalt found on Earth’s oceanic crust. The Martian magnetic field shut down may have been due to a gradual cooling and solidification of its core, or a more violent consequence of asteroid impacts which generated such tremendous damage that Mars’ liquid core lost incredible amounts of heat and the ability to flow coherently.

8 – Timescale Periods

Even if Mars never sustained life, it has been alive geologically speaking. There is profound evidence of weathering, enormous flood areas the size of Europe, dried up river deltas and extinct volcanoes. Lava, wind and water have all worked upon the tortured surface.

Mars presents to us a record of the vast period of time during which these natural powers were exerted. There are enormous mountains which have been produced by volcanic action, and in like manner, there are huge valley systems which teach us not merely the power of moving water, but furnish us with data for estimating the enormous lapse of ages during which that force operated. Deep and long ravines have been spied that have required aeons for nature to create, and yet even the sum of these years is nothing, as if merely the work of yesterday, when compared to the antecedent periods, of which there are also monuments.

In this respect, although Mars has never been subject to plate tectonics, its surface has not only been sculptured by water and weathering but also by the severe punishment of meteor and asteroid impacts. It is estimated that about 60% of Mars’ surface is cratered and that there over 300,000 craters larger than a 1km in size.

A general timescale of Mars is based on crater density and stratography. This scale has been worked into four distinct stages:

Pre Noachian Period – 4.5 to 4.1 billion years ago. This is part of the late heavy bombardment period and one of the most violent stages in Mars’ life.  It was probably around this time that the Borealis Basin and the Hellas Planitia were formed, two huge impact craters created when asteroids 60% the size of the Moon came crashing into the red planet. Around this time the Martian magnetic field shut down and the Solar wind started stripping away the atmosphere. 

Noachian Period – 4.1 to 3.7 billion years ago. This is known as the wet and warm period when water lakes covered large areas of the Martian surface. By the end of this period, Mars had probably lost most of its atmosphere and water resulting in the dry and dusty Mars we know today and the formation of dry lake beds and deltas around Arabia Terra.

Hesperian Period – 3.7 to 3 billion years ago. Volcanoes erupted over the Martian surface, especially in the Tharsis region. Huge quantities of baslatic magma flowed from Mars’ interior creating the enormous shield vocanoes we see today like Olympus Mons.

Amazonian Period – 3 billion years ago to today. This period saw the end of Mars’ more active age and the beginning of its long retirement. There was the dwindling of volcanic activity, the disappearence of most of its water and atmosphere, and the significant reduction in asteroid or meteor impacts.

9 – Outstanding Martian Features

Any brief tour of the Martian surface should highlight the following features. 

The Tharsis region is home to some of the largest mountains in the solar system. Olympus Mons is part of this area and is the tallest known mountain anywhere. Over three times the height of Everest, the now extinct volcano soars 22km into the thin air with a base width of almost 600km. If water surrounded it, the ancient shield volcano would be the size of a small island, very similar in structure and form to those making up the islands of Hawaii.

Near Olympus, spanning the planet’s crest diagonally are three older volcanoes, Arsia, Pavonis and Ascraeus Mons and although smaller in size were no less violent, generously adding to the basaltic smothered area of Tharsis. Most volcanic activity occurred between 2 to 1 billion years ago, finally spluttering out around 200 million years ago. It is due to this extensive volcanic activity that you find the northern hemisphere is sparsely cratered relative to the south. Tharsisian lava flows simply filled in many craters; some so completely that what remains are ghost craters similar to those on the Moon.

Valles Marineris is the largest valley in the Solar System. Named after the success of the Mariner 9 voyager, it is a gigantic gash stretching east from Tharsis along the equator and takes up about a quarter of the planet’s circumfrence. It was formed when the local crust could no longer take the pressure from the growing volcanic Tharsis region and simply collapsed upon itself resulting in a huge channel some 4000km long, 200km wide and up to 7km deep. By comparison, the hive of canyons, gorges and valleys that make up the majestic Grand Canyon in Arizona is dwarfed by Valles Marineris.

To the north of Valles Marineris back to the northern part of Tharsis, we come to Alba Patera Mons a huge but relatively flat volcano. Its outflow forms an ellipse which spans roughly 1400km. It is the largest known lava factory in the Solar System.

Other notable volcanic regions include Elysium and Syrtis Major which has its own volcanic beast about 1000km wide and 3km tall. The prominent dark shade of this area comes from the basaltic rock of the region and the relative lack of dust.

The Borealis Basin takes up almost half the northern hemisphere and was likely the result of a huge, planet crushing impact. As such it is a monster crater, the largest in the Solar System which required something like the size of Pluto to smash into Mars. The consequence of such a violent outrage is believed to have finished Mars’ magnetic field for good.

Hellas Planitia in the south is another huge impact crater roughly 2300km wide and around 7km deep. It is so deep that even lacking Mars’ atmospheric pressure that makes it impossible for water to form, there is enough pressure down here to allow liquid water to exist.

If you draw a line from Hellas Planitia and follow it through Mars’ interior, you’ll end up in the area of Tharsis and its gigantic volcanoes. Scientists now believe that the impact at Hellas was so great that the seismic shock wave helped form these features.

Space probes have revealed a number of caves on the Martian surface, most notably on the sides of volcanoes. These caves are thought to be treacherous shafts produced by collapsing ash and balsatic deposits. The Seven Sisters are the largest known caves on Mars, found on the flanks of Arsia Mons in the Tharsis region. These have been measured to have entrances around 250m wide and descending to roughly a kilometer. No doubt they will be found to run deeper, especially if these caves extend along the now extinct lava tubes.

Mars is also home to two icy polar caps made from a mix of carbon dioxide ice and water ice. Most of the water on Mars is locked up in these caps and it is estimated that if all the ice melted, Mars would be covered by an ocean averaging 11 meters deep.

Clouds and ice-fog form as the Sun climbs during Mars’ spring and summer. Atmospheric pressure is too low for the ice to melt and become liquid, so the water and carbon dioxide vapor rises through the process of sublimation forming clouds and a brilliant haze as seen from Earth. By winter the vapor freezes once again awaiting another new seasonal cycle. The North Pole measures some 1100km across and about 2m thick while the Soth Pole is about 4000km across with a thickness of around 3km. In comparison to the flatter and smaller North Pole, the southern cap is a landscape of pits and troughs, ice dunes and even geysers. 

The Kasei Valles is Mars’ largest outflow channel probably caused by water melting in underground reservoirs of ice. Some 3000km long and 230km wide, most of the Kasei Valles formed during the Hesperian periods some 3.5 billion years ago.

To create such a system, scientists have estimated that a volume of water equaivalent to a global ocean about 1km deep was required with a discharge rate of up to 1000 million cubic metres of water per second. Certainly, Mars wept as it was dying.

Oceanus Borealis is a hypothesised ocean that may have covered a third of Mars but which has long since disappeared. As the climate on Mars cooled the remnant of this speculative ocean froze over and was eventually absorbed beneath volcanic ash and dust. If the ocean ever existed, it is pressumed to lie hidden beneath the plains of Vastitas Borealis.

Ancient shorelines have also been identified around Shalbatana Vallis which shows evidence of an ancient lake whose area was some 210km² and about 460m deep.

Large quantities of ice more than likely lie beneath the surface in areas far from the poles. Dust and ash cover the ice from imaging but its presence has been confirmed by space probes. Dark streaks of brine still ooze along narrow channels and can grow as much as 20m a day. By winter these streaks fade away as temperatures drop too cold for even brine to remain in liquid form.

Part Two: General Observations

1 – Observing Considerations and Magnification

Famed for being such a violent and war-like character, it’s quite ironic to note that Mars is relatively small planet made up of very delicate and subtle shades of oranges, browns, slate-blues and whites. For the observer, nothing really stands out like it does on Saturn or Jupiter and because Mars only comes into opposition once every two years, most of us simply don’t have enough practice when it comes to observing the red planet.

A given session may reveal nothing more than a bright ocher globe, perhaps if we’re lucky a dark blob or two on its surface through the murky, unsteady haze of our own and Mars’ atmosphere. We browse a detailed Martian map only to find it too difficult to identify what we were looking at, which side of the planet our telescope was focused and even on some nights where the poles were to tell north from south. Following such frustrations, it should come as no surprise to understand why many astronomers find Mars quite a disappointing planet.

Nothing is given in astronomy, especially when it comes to viewing Mars. Jupiter is about three times the size of Mars and to see Jupiter with a significant amount of detail, we’ll need around 160x to 200x magnification which means that to get a similar view of Mars, we’ll need an outrageous 600x.

As impressive as that sounds, we are never going to get the kind of viewing quality that can allow for this type of power. 99% of Earth’s atmosphere lies in a layer about 30km thick and you’re at the bottom of it looking up. Adding to this problem is the fact that most atmospheric disturbances take place in the first 15km or so from where you stand, exactly where Mars’ own light is being refracted by air cells causing shimmering in the eyepiece. If you view from an urban surrounding although light pollution isn’t going to affect your image quality too much, warm air coming from buildings and mixing with the cold night will also help to warp the image. 

So a compromise is needed. In terms of aperture, I feel that Mars begins to get interesting around 6” in a reflecting type of telescope and around 4” to 5” in a good refracting telescope. In terms of power, we’ll need 200x to 250x to start tweaking some significant Martian detail which still means seeing conditions will have to be very good. As such, Mars is not a particularly giving planet.

However, there are other ways we can help ourselves.

2 – Time, Patience and Comfort

Atmospheric conditions can wreck havoc on our observations. Light diminishes and turbulence increases the lower Mars appears relative to the horizon, so try to view Mars as high as possible in the night sky.

Mars also requires time, patience and comfort. You need the patience to spend time at the eyepiece waiting for those brief moments of atmospheric stillness where everything is just perfect and comes into view. To have this kind of patience you need to be comfortable and so you need to be seated. This cannot be stressed enough. If you want to do some serious planetary viewing of Mars, do yourself a favour and buy or make for yourself an observing chair.

At this junction, we can also point out the importance of sketching. Typically, the general advice for seeing more on Mars is to up the aperture a little or improve on the quality of optics and telescope’s contrast but of equal importance is to simply slow down. There are two essential features to viewing Mars: locating the planet and observing it. The former requires the technique of knowing where to look, the latter, asking questions about the object and recording them in either written or sketch form.

Anything at a distance just glanced at will always look like a featureless something but the trick in visual astronomy is to go beyond this and practice seeing - picking out the subtle and yet complex features and textures of the given object. Sketching really aids this process, but so too recording the observation in written form or talking into a digital recorder etc. There's no right or wrong way of going about it, so long as you spend a little time on your Martian sessions really trying to observe rather than just looking.

Contrary to what folk may happen to think, the point of sketching is not to create some beautiful rendering of the object itself, but rather to train your eye to see better. With practice, it's amazing what the eye and brain can do. Overtime you really start to pick out features that the casual observer simply cannot see. I'm so convinced about the power of sketching that I believe with a little practice and care it will add a virtual inch to your aperture. If you sketch while seated, you can add another 1" for being comfortable.  That kind of power increase is priceless.

3 – Aphelic and Perihelic Oppositions

A Martian day is a little longer than on Earth and it rotates on its axis once every 24.6hrs. This difference of about 40 minutes relative to our own rotation is quite handy in terms of observation. If you can observe Mars at the same hour on every clear night possible, you’ll note a subtle lagging towards the planet’s east as those features of the previous day come into view just a little later on each progressive evening. This difference amounts to about 9º of longitude east every day which means that over a period of about 40 days, you can complete a tour of Mars’ surface.

The best time to observe these subtle changes on Mars is when it is at opposition. This occurs once every two years when Mars is opposite the Sun relative to our own orbit and is virtually 100% illuminated and at its largest apparent diameter for that given apparition.

As we approach Mars’ opposition more dusky features and the bright glare of the polar caps come into view. However, not all oppositions are equally favourable. Aphelic oppositions place Mars further from Earth and the planet’s disc is generally around 15” arcseconds in apparent size. Perihelic oppositions, on the other hand, are what most amateur astronomers look forward to. The planet is closer to earth and its disc has now grown to an apparent size of roughly 25” arcseconds, so obviously appears a lot bigger.

Armed with a small telescope, you can work out not only the seasons on the planet but how the tilt of Mars gives good indication of the type of opposition you can expect. When Mars is at an aphelic opposition, its North Pole is tilted towards the Sun, which means it is summer in the north while the south is in its extremely long and severe winter. At such times, northern features are easier to discern.

When Mars approaches a more favourable perihelic opposition, the South Pole is tilted towards us, making the duskier features of the south more presentable. Here it will be summer in the south and winter north. The summer at such times is shorter but warmer, causing the southern polar cap to melt more rapidly than it does in the northern pole cap during its summer.

By way of a rough estimate, when Mars is about 15” arcseconds in apparent size, 1” arcsecond is equal to about 450kms and when Mars presents itself as some 25” arcseconds, 1” arcsecond is equivalent to about 270km.

4 – Martian Maps and Albedo Features

Looking at the array of Martian maps, you’ll find two general features, areas once thought to be seas and those once thought to be land. In essence these are just different albedo features, areas differentiated by apparent brightness caused by sunlight being reflected back from another world.

The maps I include below are some of the best I have seen which reflect to various degrees what you will be likely to see when observing in good conditions.

Seas are the lighter features and include Sinus Meridiani, Mare Erythraeum, Mare Sirenum (Sea of Sirens) and Aurorae Sinus (Bay of the Dawn).

Lands are the darker features such as Syrtis Major, Arabia Terra, Amizonis Plasatia (Amazonian Plain).

The north where the Polar Cap lies is known as Planum Boreum while the south is known as Planum Australe, the Northern and Southern Plain respectively. If it is summer in southern hemisphere on Mars, then the South Pole will be tilted towards us. If summer is in the north, then the North Pole will be tilted towards us.

At a given opposition one of these poles will be visible but due to its relatively small size and the fact that it is shrinking due to sublimation caused by the summer Sun, it might be quite hard to see. If you do observe something big, bright and icy that you feel ought to be a polar cap, big, then it's more than likely Hellas, a huge impact basin which often fills with mist and fog and looks more like a polar cap than the Martian polar caps themselves.

The most obvious dark features you'll see on a night of good seeing are Syrtis Major, Terra Sirenum and Terra Cimmeria covering some 5000km and the Cydonian and Erythraeum area. These albedo features all have distinctive shapes. For example, Syrtis Major is often said to resemble India or Africa with bright Hellas at the edge. Terra Sirenum and Cimmeria are more elongated, Erythraeum is a large and darker blob while Cydonia is rather curved.  

If the night’s seeing is favourable, you can also try to discern more subtle features.  The Eye of Mars is near Solis Lacus which some observers say looks like a human eye peering back at you. You'll also be able to see Niliacus Lacus, Acidalium, Sinus Sabaeus and Sinus Meridiani which are quite dark and dusky areas of Mars.

By contrast to these darker albedo features, predominately lighter areas are typically around the Tharsis region, home to the tallest mountain and biggest volcanoes in the Solar System. The volcanoes are so big that even from Earth with our small telescopes we are sometimes able to see clouds floating on top of them which in the eyepiece will appear as rather small misty-white patches. It really is well worth your time looking out for them.

There is always a dusty haze in Mars’ atmosphere but sometimes you will try to look at Mars and even on a great night of seeing will not be able to see the albedo features with clarity. Martian desert storms are very unpredictable and extremely violent and you’re never going to know when the next one will come crashing in and cover everything.

Usually these dust storms last a few days, but sometimes they last for weeks and even months. If you’re fortunate enough to see one, you might be able to note a significant brightening of the fiercer areas as the winds hurtle through the region kicking up dust devils and huge spiraling columns of Martian regolith.

At the end of the evening, even if you cannot see anything on Mars and only experience a shimmering, blood red globe try not to feel too disappointed. Think how fortunate we have been are to even be able to experience another world out there floating in the vast darkness of space.

For further reading I can recommend the following books:

Destination Mars by Rod Pyle.

Mars & How To Observe It by Peter Grego.

Edited April 9, 2014 by Qualia

[Charic]

+1 Should be pinned.

[John]

+1 Should be pinned.

I agree. It's a superb guide to Mars and observing it 

Many thanks for compiling and posting this 

[cantab]

Excellent guide, thanks.

[jetstream]

Qualia,thank you for taking the time to put this together,it is fantastic.

[Pig]

Nice one Qualia, as usual

[cotterless45]

Excellent ! Something that should be pinned, a lovely resource,

Nick.

[RCompassi]

Should be pinned!

[YKSE]

Great write up, very infromative and excellent guide. +1 for pinned!

[Vega]

Very informative post. Thanks for that.

Here's some info on viewing mars this opposition.

[stevend]

Qualia, this is fantastic.

[HIP3802]

Qualia, another excellent and informative guide. Many thanks for taking the time to put this together in such a readable way.

Martin

[Pondus]

Highly interesting post from you again.

I need to read it many times though, to try to get the info to stick to my somewhat mediocre brain..

Forgive me for asking these novice questions (especially if you`ve already have covered these questions in the post  )

1. If I was walking by foot on Mars, I would not see when I 'entered' Syrtis Major?

2. April 2014 : Mars is in an 'aphelic' opposition, it will be perihelic opposition in 2016?

3. Is it summer in the northern hemisphere right now?

Regards

Rune

[Moonshane]

superb Rob! if only Mars was as generous at revealing details.

[C7tsj]

Excellent, very informative.

[bingevader]

Excellent, as always. 

[RichM63]

What an excellent and highly informative article.

Evidently written by a 'natural' educator.

I look forward to discovering more from this author.

Cheers,

Rich

[Toymaster]

Excellent - Thanks for posting.

Should be pinned.

Adrian

[Qualia]

Thank you everyone for your kindness and generous thoughts. My evening has been made a lot brighter. Thank you and I hope in some way the post will help our stargazing adventures.

Rob

[Mike73]

I've just learnt so much from reading through this, thanks for taking the time to add posts like this to the forum.

I think the forum needs another section to it called 'Qualia's Corner' 

[Qualia]

1. If I was walking by foot on Mars, I would not see when I 'entered' Syrtis Major?

2. April 2014 : Mars is in an 'aphelic' opposition, it will be perihelic opposition in 2016?

3. Is it summer in the northern hemisphere right now?

Hiya Rune,

With regards to the first questions, I'm no better experienced than anyone else here to answer but will try to make an educated guess.

I imagine what we would be looking for if strolling on the edge of Syrtis Major is something like a transition zone from one type of terrain to another. That's pretty easy to write but I wonder how easy it would be in practice to pinpoint its exact location. Even on Earth where, say, arid desert land and grass land meet, it's not easy to say exactly where one meets the other for they merge very gradually. What would complicate matters further is that any boundary we arbitrarily chose would shift from season to season as storms whirled and kicked about that imaginary line.

However, the notion of a transition zone assumes there would be something like a transition zone and I'm not entirely convinced we would really find one on Mars. Sure, there would be something of the sort around the poles, for example, but elsewhere, technically speaking, a desert is described as an area having an annual rainfall of less than 300mm, so Mars is a kind of gigantic desert. The dark and light features we see through our telescopes is an albedo effect - the way we see the sunlight reflected on the surface - but I wonder how real that would actually be if we were on Mars taking our stroll  . 

You're quite right in number 2. This year we're enjoying an Aphelic Oopposition. Mars at its maximum is around 15” arcseconds in apparent size and its North Polar Cap is tilted towards the Sun (and us). In 2016 we will enjoy Perihelic Oppositions but it won't be one of the best.

With regards to question 3, yes. The northern hemisphere is enjoying its long Summer but it's not the kind of summer we enjoy here on gorgeous Earth. Days will generally reach around 15ºC, they may have a maximum of roughly 27ºC. And when night kicks in those mild temperatures are going to drop very rapidly to something like a fresh 140ºC below zero and even reach as low as minus 150ºC .

[Pondus]

Heya

Thank you for taking your time answering me, much appreciated.

As I said in my first post on this thread, I need to come back and read it again and again...

But now I`m positive that I saw the northern polar cap with my Orion XT8i  night of april 9th ( upside down image still confuses me and my memory a bit, sketching might not be such a bad idea..)

Again Thanks

Rune

[RichM63]

@Rob, do you have an off site link to your articles/edu content, I would love to be able to study in more depth.

Cheers,

Richard

[Qualia]

Hiya Richard. Thank you for your kind message. I don't have any site or any other place I write. SGL is my only on-line haunt. I take notes on the stuff I'm interested in and swot a little as a kind of hobby and then from time if I think it might be SGL fitting, I'll post something up here, or send something off to those interested. For many years my main interest has been philosophy but recently I've been getting into more 'earthy' subjects. If you let me know the kind of thing you're interested in, I might have something I can pass on .

Edited April 11, 2014 by Qualia

[KevUU]

Another knock-out blow from you Qualia, really well researched and constructed and delivered. Thanks for making the effort on our behalf

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