The Moon, Jupiter & The Winter Circle | Mars & Saturn
Tonight, as darkness falls, the Moon and Jupiter will lie in the sky very close to each other, in the constellation Gemini the Twins.
The Moon is almost half-lit, while Jupiter is the most brilliant ‘star’ in the sky. The Moon takes 27.3 days to complete its sidereal orbit, so it stays for about 2.5 days in each of the twelve zodiacal constellation, while Jupiter, which completes an orbit around the Sun every 12 years, spends about one year in each constellation.
The two celestial bodies will be in the midst of the Winter Circle, or Winter Hexagon asterism, formed by the most dazzling winter stars: Capella (Auriga), Castor (Gemini), Pollux (Gemini), Procyon (Canis Minoris), Sirius (Orion), Rigel (Orion) and Aldebaran (Taurus).
A very red Mars rises in the East, in the constellation of the Virgo, and is soon followed by Saturn, which resides in the Libra segment. In two days, on April 8, the Sun, Earth and Mars will be on a straight line, with the Earth in the middle. This event happens once in a Mars synodic period (780 days), and it is called Mars-Earth opposition. When Mars is at opposition, it is in the middle of its retrograde loop and the distance between the two planets will be relatively small; its disk appears larger and it has a negative magnitude. This is the most favorable time for viewing Mars.
For the entire month of April, Mars will stay bright and big in the sky, from dusk till down, but circle the night of Tuesday, April 8, when the Earth will be closer to Mars than it has come for almost six-and-a-half years.