Return to Newsletter Index

Midnight Warrior

by Perry Pezzolanella

Mars is the only planet where detail can be readily seen on a solid surface. It is not an easy planet to observe because it is usually too small to see any detail. The best time to observe Mars is around and during opposition when it is closest to Earth and therefore at its largest, brightest, and up all night. Unfortunately, the speed of both Mars and Earth around the Sun are not much different with Mars being the slower of the two, which means that oppositions occur roughly every 26 months. Not all oppositions are decent due to Mars’ highly elliptical orbit. The result is that Mars can come as close to Earth as 34.6 million miles and be as large as 25.2 arcseconds across, while at other times it is as much as 63.0 million miles and barely 13.8 arcseconds across. The rest of the time Mars is usually on the far side of the Sun, barely 4 arcseconds across, featureless, and no larger than Uranus through a telescope.

Mars offers plenty to observe as long as patience is applied. The overall bright, peach-like hue is a vast global desert. The ruddy hue is due to iron ores in the soil similar to red clays on Earth, which causes Mars to appear as a reddish star in the night sky. The ancients feared this unusual bloody-looking, bright star and since they associated blood with war they named it in honor of the “God of War”. The darker features on Mars are vast rocky outcrops that have been blown free of brighter dust. These areas appear tan or brownish, but may appear greenish due to the brighter, redder hues that dazzle the eye and create a greenish after-image on the retina. The darkest regions on Mars include a vast triangular area known as Syrtis Major, and a pipe-shaped area complete with a bowl and stem called Meridiani Planum and Sinus Sabaeus. Another darker region known as Solis Lacus appears like a dark spot and is called the “Eye of Mars” since it resembles the pupil of an eye. Using an orange (W21) filter will aid in seeing the dusky features as it will increase the contrast.

The polar ice caps are the most obvious feature on Mars as they are the brightest features. It is fun to follow the changes in size as the Martian year progresses. As spring advances in one hemisphere the ice cap will steadily shrink. The northern ice cap never completely vanishes, but the southern ice cap nearly does. This is because Mars is closer to the Sun during the southern summer and warms enough to melt most of the ice cap. It is worth looking for details within the ice caps. Sometimes the ice caps may not melt evenly or may break away, leaving tiny white specks along the perimeter that will eventually melt. Around the perimeter of the receding ice cap is a dark belt called the melt line that looks like damp sand deposited by melting ice, but it is most likely caused by winds blowing off the ice cap and sweeping the immediate region free of brighter dust.

The atmosphere can also reveal detail from subtle to downright obvious. White clouds are subtle and seasonal, consist of water ice, and usually form during the warmer seasons. They become more numerous and cover a larger area of the poles as the ice caps melt or grow. These clouds occur close to the surface and are probably fogs. They are also seen along the morning terminator as a haze that dissipates after sunrise. Clouds also form near the largest volcanoes and appear as bright spots. Yellow clouds are the ominous signs of a dust storm, which can develop rapidly into a global storm obscuring nearly all surface detail for months, making them quite obvious. Such storms occurred during 1971, 2001, and the infamous 2018 storm that forever silenced the Opportunity rover after over 14 years of exploring Mars. Dust storms are the most dynamic weather phenomenon on Mars because they grow, move rapidly, and eventually dissipate.

Mars is an exciting planet to observe when the conditions are perfect which can create many memories. All that is needed is plenty of patience and dedicated observing, and with time the eye will become trained to see all the fine detail that Mars has to offer.