The waning crescent moon will form a triangle with the Red Planet and the bright star Antares in the morning sky on Monday (Jan. 20), and you can catch the trio in the morning sky before dawn.
Mars will be in conjunction with the moon — meaning they share the same celestial longitude — at 2:12 p.m. EST (1912 GMT), but they will be invisible in daylight for skywatchers across the U.S. at that time. However, the pair will be observable for a few hours before sunrise.
In New York City, for example, Mars rises at 3:56 a.m. local time, and the moon rises about half an hour earlier. Antares will be the last of the three to rise, at 4:07 a.m. local time in New York. The sun will rise there at 7:15 a.m. local time, which means skywatchers have about three hours to see the celestial trio before they fade into the sunlight.
During their encounter on Monday morning, the moon and Antares will be in the constellation of Scorpius, the scorpion, while Mars will be in the neighboring constellation of Ophiuchus, the snake bearer.
Shining only at first magnitude, Mars will be relatively dim compared with Antares, which is the fifteenth-brightest star in the night sky. The Red Planet will be at its brightest on Oct. 13, when it reaches opposition, or the point in the sky directly opposite the sun.
- When, where and how to see the planets in the 2020 night sky
- Night sky, January 2020: What you can see this month [maps]
- Astronomers map atmosphere of dying supergiant Antares