As seasons change and a new spacecraft sets up shop around Mars, sky-watchers can see the red planet face off with a rival, a treat along with other celestial treasures.
September equinox. The autumn season in the Northern Hemisphere and spring in the southern counterpart officially arrives on Tuesday, September 23, at 2:29 Universal Time (10:29 p.m. on Monday EDT).
For most of the calendar year, Earth’s axis tilts either toward or away from the sun, resulting in the seasons. However, during the equinox the Earth’s north-south axis is neither tilted toward (summer in the Northern Hemisphere) nor away (winter in the Northern Hemisphere) from the sun, so both Northern and Southern Hemispheres receive equal amounts of sunshine.
The word “equinox” comes from Latin meaning “equal night” and refers to the 12-hour-long day and night that occurs only on these particular days of the year.
Maiden and the moon. Just after sunset on Thursday, September 25, look for a close encounter between the razor-thin crescent moon and the bright star Spica, the lead member in the constellation Virgo, the Maiden.
The celestial pair will be visible easily through binoculars, but will be challenging to see with the naked eye because they will be so low to the western horizon (at 5 degrees altitude) amid the glare of the sunset. Observers in more southerly latitudes, particularly around the equator, will have a better line of sight as both the moon and star will hang about 15 degrees above the local horizon.
Once spotted, the cosmic pair will make for a pretty sight, since they will be separated by less than 5 degrees, equal to the with of your fist held at arm’s length.
Lord of the rings. Sky-watchers gazing toward the southwestern sky at dusk on Saturday, September 27, can see the waxing crescent moon join a creamy-colored Saturn on its upper left.
Small backyard telescopes will reveal the gas giant’s magnificent rings, which span nearly the same distance as that between the Earth and its moon.
Mars and Antares. By the next evening, Sunday, September 28, the red planet makes its closest approach for the year to its big rival, Antares.
The two distinctly red-orange objects will appear less than 3 degrees apart. That apparent separation is equal to only six full moons side by side. It is amazing to think that while they look close together and appear similar in nature, they couldn’t be more different in reality.
Mars is a neighboring planet lying only 140 million miles (225 million kilometers) from Earth, while Antares, the brightest star in the constellation Scorpius, is a whopping 600 light-years away. A red supergiant star with 18 times the mass of our sun, Antares is so large that if it replaced our sun, its outer edge would reach beyond the orbit of Mars.