SJAA Ephemeris February 2010 | SJAA Home | Contents | Previous | Next

The Shallow Sky

Roving, or wasting away?

Akkana Peck

Sketch of the eye of Mars by the author.


This February’s skies don’t have a lot of planets, but what’s there is worth watching. Saturn is there for the looking, showing a ring tilt of 4.5 degrees. Most of the other planets are too close to the sun to observe right now. But that’s okay ... because this is the month to look at Mars! It’s just past its January 27 opposition and visible high in the sky all night, transiting at over 75 degrees. That’s much higher than we’ve seen it for a long time, so if you get lucky with the weather you should be able to get very crisp, steady views. Dust off those short-focus eyepieces and crank up the power!

As February opens, Mars is showing an interesting area around 8 p.m. PST: the area around Sinus Meridiani and Lacus Solis, the “Eye of Mars”. Lacus Solis is a dark circle surrounded by lighter areas – it really does look like an eye if you catch it at the right angle. It’s south of the equator, and since Mars has its northern hemisphere tilted toward us, the “eye” may be a bit more foreshortened and not quite as easy to see as in some past oppositions.

To the north, the Tharsis plateau presents a blank, nearly featureless view to most earthbound observers. You may occasionally be able to see a white haze from the clouds blown up the slopes of the three huge Tharsis volcanoes. But the western limb of the planet shows some interesting dark areas, and by the first weekend in February they’ll be showing well. In the north, dark Mare Acidalium is dead center at around 9 p.m. PST, with Niliacus Lacus nearer the equator and the more subtle Nilokeras hanging off to the east. How much detail can you see in the shape of Nilokeras?

Look, too, at the polar area. Mars’ north pole is pointed slightly toward us, and it’s spring there, so you might still be able to see a fair amount of the northern polar cap. Not sure which way north is? Mars’ north is pretty much the same as ours, so nudge your telescope to the north while looking in the eyepiece to see which way it moves.

The southern hemisphere on that first February weekend is even better, showing Margaritifer (“Wastin’ away in Margaritifer”) and Mare Erythraeum. Look for lots of dark “fingers” extending northward – how many can you count? On a steady night you can spend a lot of time exploring the complicated shapes of northern Erythraeum, especially if you try sketching what you see (regular readers will know I’m a huge sketching advocate, especially for subtle and changing planets like Mars and Jupiter).

By 9 p.m. on the following weekend, Feb 13 – or just after dark the weekend before – Sinus Sabaeus is front and center. This slim dark feature should be easy to spot in the southern temperate zones, with the larger Sinus Meridiani trailing it to the east. In the north, the features are a lot more subtle – how much detail can you see on Protonilus? You should still be able to see the dark shape of Acidalium on the northeast limb. Meanwhile, in the southwest, Mars’ most prominent feature, Syrtis Major, has started to become visible.

A week later, on the 20th, Syrtis Major is centered around 9p.m., showing its Africa shape (some think it looks more like India). Along the limb on the south edge of Syrtis Major is the very light area Hellas. With the south pole pointed away from us, it’ll be easy to mistake Hellas for a polar cap – in fact, it may look more like a polar cap than the real polar cap we can see, the northern one, on the opposite side of the planet. But Hellas is really just a huge impact crater, a low area of Mars that collects frost in some seasons and so tends to look lighter than everything else. At least, that’s usually the case. But this year, since it will be fall in the southern hemisphere, Hellas may not be as light as usual. Will it still look like a polar cap? Take a look and find out.

Finally, through the last week of February, Mare Cimmerium and Mare Tyrrhenum are visible, two dark areas entwining along the southern half of the planet. As you look, spare a thought to the poor Spirit rover, still fighting for her life near the northeast edge of Cimmerium. It’s looking bad for the little rover, but she moved a wheel last month and the latest I heard was that they might be able to tilt her to get enough sunlight to survive the winter. Cross your fingers!

Meanwhile, in the north, subtle features like Elysium, Thoth and Trivium Charontis will test your seeing abilities. Good thing you’ve had all month to practice your Mars observing!


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