The Moon Passing close to Venus and Mars (January, 2017)
The medley of the Moon, Mars, and Venus
2017 starts with the medley of Mars, Venus, and the Moon in the western evening sky. After sunset, Venus shines brightly low in the southwestern sky with a magnitude brighter than -4 . You can see Mars with a magnitude of around 1 to the upper left of Venus. The thin waxing Moon, having passed crescent phase, appears to approach Venus and Mars in turn.
After sunset on January 2, the Moon comes within about 1.5 degrees of Venus. The apparent diameter of the Moon is about 0.5 degrees, so this means that they appear to come within 3 times that distance. On the following day, January 3, the Moon comes within about 0.5 degrees of Mars. The time of closest approach is just before sunset. The darker the sky gets, the more clearly Mars can be seen shining red near the Moon.
After that, the Moon waxes and it moves away from Venus and Mars. Venus’s elevation becomes higher and it also becomes brighter. On January 31, the Moon again passes close to Venus and Mars, which are even closer to each other than they were at the beginning of the month, forming a beautiful spectacle.
You can look up the rising and setting times for the Sun and the Moon, and the phases of the Moon in the “Koyomi Station” of the NAOJ Ephemeris Computation Office. You can find the appearance of the Moon and planets as seen from a typical city under “Sky Viewer.”