December skywatching highlights: The skies are full of mesmerising astronomical marvels in the last month of the year. The Moon will make a close approach to Jupiter towards end of December. On December 7, Earth's natural satellite will cover Mars completely, in an event called an occultation. This is an event in which an object is hidden from the view of an observer because of another object passing between them.
The occultation on December 7 will be visible across the United States, except for the Southeast and East Coast. This is because in these places, the Moon will graze closely past the Red Planet. People can find Pegasus, the winged stallion, high overhead throughout December.
Here are the most interesting cosmic marvels stargazers can witness in the December sky.
Venus and Mercury
At the beginning of the month, stargazers in India with a clear view of the horizon can search for Venus and Mercury during sunrise, just a few degrees above the skyline.
Lunar Occultation
On December 7, people can observe one of the magical moments when the sky changes dramatically before their very eyes. People can witness a phenomenon called lunar occultation. The Moon will pass in front of, or occult Mars. However, the phenomenon will be visible only in parts of North America, Europe and Northern Africa. Other regions of the world, including India, can watch the spectacle online.
While the Moon passes in front of planets in the night sky several times every year, and generally occults Mars itself a couple of times per year, each occultation is visible from only a small portion of Earth's surface. Hence, it is not extremely common for any particular spot on Earth to see a lunar occultation frequently.
Pegasus, the winged horse
On December evenings, people can find a constellation called Pegasus in the sky. The astronomical marvel is called Pegasus 'The Winged Horse' or Pegasus 'The Winged Stallion'. In Greek mythology, Pegasus was a beast who went on adventures with the hero Belaraphon, and later carried the thunderbolts of the Greek god Zeus himself. Zeus rewarded Pegasus by placing the latter among the stars.
In astronomy, Pegasus is one of the largest of the 88 constellations, and the Great Square is its most prominent feature, and the key to finding it in the sky. The Great Square is an asterism or pattern of stars.
Due to the brilliant Jupiter, people can easily locate Pegasus in the December sky this year, according to NASA. The Great Square will begin about 15 degrees to the north of Jupiter.
Pegasus is a good starting place for finding one's way to other features in the night sky, making it a useful constellation for stargazers. Pegasus contains a number of dazzling deep-sky objects, including globular cluster M15, and the dancing galaxies of Stephan's Quintet.
Moon, Saturn and Jupiter
From December 25 to 31, stargazers can see the full Moon slip past Saturn, and then past Jupiter.