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Red Star Sparkling

by Perry Pezzolanella

A bright reddish star will sparkle during the crisp, long nights as the holidays approach. It will be easy to find as it will be the brightest star in the sky and glow like a famous reindeer’s nose. This star, Mars, is back after a two-year hiatus. Mars has a decent opposition on December 8 when it will be up all night, but due to its highly elliptical orbit, it will be at its closest, largest, and brightest on December 1. On that date Mars will be 50.6 million miles from Earth, 17.2 arcseconds across, and will sparkle at magnitude -1.9. Even though Mars will be smaller than past oppositions it will be high in the sky above the worst atmospheric turbulence.

Mars is a favorite to observe because it is the only planet where details on a solid surface can be seen. It is a rusty desert world of windswept sand dunes, towering volcanoes, vast canyons, craters, and two polar ice caps. These polar ice caps are the easiest to see and are composed of frozen water and carbon dioxide. During this opposition both polar ice caps will be visible as it will be spring in Mars’ northern hemisphere. The northern ice cap will be the larger of the two as it has just emerged from winter and has yet to begin sublimating, while the south polar ice cap is experiencing autumn and has already shrunk over the summer. All the familiar dark and bright features visible during prior oppositions will be visible, provided there are no dust storms. The darker, brownish areas are primarily dust-free rock outcrops with the largest and darkest being a wedge called Syrtis Major. Meridiani Planum is where the Opportunity Rover explored from 2004-2018, and Solis Lacus looking like a dark eye is often nicknamed the Eye of Mars. Hellas is a deep impact basin over 1000 miles across that is filled with very fine, highly reflective dust that can be confused with clouds or the south polar ice cap. Mars demands extreme patience when it comes to observing; several nights of observing will train the eye to focus on detail. Larger telescopes will improve the view along with the use of orange or red filters. An orange-green filter combination will cut the glare and enhance the dusky surface features while closely preserving the natural color. Mars will be very high in the sky near the Gemini-Taurus border where turbulence is minimal.

The first row of diagrams that follow show a complete surface map of Mars with the most prominent features visible as well as the polar ice caps. Three different global views follow with the darkest and most prominent surface features shown. The dates in the third row indicate when these features will be nearly centered on Mars at 11PM EDT (10 PM EST). These provide views for a few hours either way or a few days around the given dates. Since Mars rotates on its axis in 24 hours and 37 minutes, these features will shift throughout the night. The rotation rate from Syrtis Major to Sinus Meridiani is six hours. From Sinus Meridiani to Solis Lacus is another six hours. If Solis Lacus is visible, then it will be another twelve hours before Syrtis Major returns to view. The fourth row indicates the change in size and brightness for Mars during this apparition.

The best time to observe Mars is when it is larger than 10 arcseconds across. This will occur from September 5 through February 8, which will provide ample time to train the eye enough to make sketches, or to take photos or videos. The retrograde path of Mars among the stars from October 30 until January 12 can also be observed and plotted. Take note of the changing phase of Mars as it becomes noticeably gibbous by late February with only 90% of its disc being lit by the Sun as seen from Earth.

Due to its very elliptical orbit, not all oppositions of Mars are good. This one is about average, but the oppositions of 2025 and 2027 will be worse before growing better in 2029 and 2031. The opposition of June 27, 2033 will be the best one since 2018, but the best one since the historic 2003 opposition occurs on September 15, 2035 with Mars at an impressive 24.6 arcseconds across. Be sure to observe Mars during the festive holiday season as Mars is a gift that keeps on giving, but do not confuse it with another glowing red star that might gracefully glide across the night sky on Christmas Eve!