Starry skies abound this holiday week, with treats for both the novice and the seasoned sky-watcher. The moon joins bright stellar landmarks, while brilliant star clusters take center stage in the sky.
Celestial charioteer. With the moon absent from the early evening sky on Monday, December 23, it’s a great time to look instead toward the southern sky for the pentagon-shaped constellation Auriga—the charioteer.
Auriga’s lead star, Capella, is the sixth brightest in the entire sky and shines with a fiery, bright orange hue. While countless number of distant stars serve as a backdrop to the constellation, Capella sits quite close to our solar system—some 42 light-years from Earth. That means we are glimpsing light that departed from Capella in 1971, the year when the Apollo 14 and 15 missions landed on the moon, the Academy Award for best picture went to Patton, and baseball player Hank Aaron hit his 600th home run.
Also known as the “Shepherd’s Star,” Capella is actually a pair of giant stars, each one three times the size of our own sun. Only about 74.6 million miles (120 million kilometers) apart, they are too close to be visually separated even in telescopes.
Auriga’s gem trio. On Christmas Eve, December 24, look again toward Auriga, and see nestled within its midsection an impressive trio of star clusters. Visible to the unaided eye as fuzzy patches in dark skies, binoculars within city limits will reveal their true jewel-like beauty.
The faintest is M36, which lies right in the belly of Auriga. It contains about 60 stars huddled together at a distance of 4,100 light-years away. Right next-door in the direction of Auriga’s lead star Capella, M38 is the most widely scattered cluster of stars, 100 of them residing some 4,200 light-years away.
The most stunning, however, is M37, found just below the pentagon-shaped Auriga. Containing over 150 stars, it is dominated by a distinctly orange-tinted star at its center and is at an awesome distance of 4,400 light-years.
Red and silver Christmas. At dawn on Christmas Day morning, December 25, look for Mars parked next to the last quarter moon high in the southern sky. The ruddy planet resting next to Earth’s silvery companion will make for a stunning color contrast when seen with the naked eye. The pair will appear to be less than 5 degrees apart—about the same as the width of your fist at at arm’s length.
Luna visits Spica. The moon will continue to glide toward the east every night, and on Thursday, December 26, it will have a stunning close encounter with brightest member of the constellation Virgo. Spica is a blue-white giant star located about 263 light-years away from Earth.
Remember, that means that we see Spica as it was 263 years ago—the length of time it takes for its light to arrive at our planet. So when you look at Spica, you’re seeing light that left on a journey in 1750, the year when famed music composer and musician Johann Sebastian Bach died, the first playhouse opened in New York City, and the population of Europe reached 140 million.
Moon joins Saturn. Did Santa send you a new telescope for the holidays? Then at dawn on Saturday, December 28, and Sunday, December 29, the waning crescent moon will conveniently point the way to the ringed world, Saturn, low in the southeastern sky. To the naked eye, Saturn will look like a bright yellow-tinged star, but a small telescope can reveal its rings easily—even some of its larger moons, such as Titan.
Those magnificent rings are tilted just right, so as to give a beautiful view of its flattened disk-like nature. The entire ring system spans about 162,000 miles (260,000 kilometers) across, which would make the entire planet and its rings fit easily between the Earth and moon.
Meanwhile, Titan is the largest moon of Saturn and the second largest in the entire solar system. It will appear that morning to the planet’s left, in line with the rings, in a low-magnification-eyepiece view.
And in case you are wondering, Saturn is now about 930 million miles (1.5 billion kilometers) away, while the moon is a mere 249,000 miles (400,000 kilometers) away from us on Earth.
Tell us—what amazing sky phenomena have you seen lately?