Over the next several days the Moon, as it waxes toward full phase, will follow the ecliptic as it passes by some of its solar system colleagues. Starting on the 15th, a few degrees east from the blue-white star Spica in Virgo the Harvest Maiden, the waxing gibbous Moon will then pass a few degrees from Mars on the 16th and 17th. Then on the 18th the nearly full Moon will be about 3o from Saturn, and that night ending this month’s lunar sweep along the ecliptic and bright planets.
This animated graphic shows an 'atlas' view of the area along the ecliptic and the the Moon's daily path from June 15th to the 20th. The celestial equator is the curved red line and the ecliptic is the green line.
There are two distinct motions, and one subtle motion shown in this animation.
-Planets are in motion with Saturn and Mars on the move with Mars moving toward the west as it retrogrades. On a day to day basis the subtle shift in the position of Saturn and Mars each day is relatively small. Saturn moves 0.033o each day (360o/10,755 Earth days), and Mars each day moves 0.52o (360o/687 Earth days) .
-The Moon orbits from west to east so each day at the same time the Moon is further to the east, or rises (sets) later.
-The daily shift in the sky from east to west due to the Earth’s revolution around the Sun. The sky shifts about 1 degree each day or celestial objects, like stars, rise (and set) about 4 minutes earlier each day.
The graphics below are set for 10 pm CDT on the dates indicated.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.