This evening – June 8, 2014 – the moon couples up with Spica, the brightest star in the constellation Virgo the Maiden. No matter where you live worldwide, look first for the moon. The star closest to it on the sky’s dome will be Spica in the constellation Virgo. The red planet Mars shines to the west of the moon and Spica. Golden Saturn shines to the east of the moon and Spica. Mars will be brightest, then Saturn, then Spica.
Although Spica ranks as a first-magnitude star, the glare from tonight’s bright waxing gibbous moon might make Spica look less than spectacular this Sunday evening. It should be easier to see the planets Mars and Saturn, because both planets outshine Spica. Moreover, the planets are farther than Spica from the moonlit glare on June 8.
Throughout the night, from everyplace worldwide, the moon, Spica, Saturn and Mars – plus the other stars in tonight’s starry sky – will go westward across the sky. They go westward throughout the night for the same reason that the sun goes westward during the day. The Earth spins from west-to-east on its rotational axis, causing all these heavenly bodies to appear to travel from east-to-west every day. This apparent daily movement caused by the Earth’s rotation is called diurnal motion.
If you watch the moon from day to day, you can detect its true orbital motion around our planet.
For example, tomorrow evening – June 9 – note the moon’s change of position relative to Spica. The moon will have moved eastward, toward Saturn and away from Mars. As always, the moon goes full circle in front of the stars of the Zodiac in a little less than one calendar month, and will meet up with the star Spica again around July 5, 2014.
Bottom line: The June 8, 2014 moon is near the star Spica on the sky’s dome. Mars is to the west of the moon. Saturn is to the east of the moon.