Get ready for a celestial double feature unlike anything seen in decades: Mars is about to make its closest approach to Earth in 15 years—just as the full moon blushes red in the longest “blood moon” eclipse of the century.

Both the moon and Mars will dominate the overnight hours on July 27 and into the morning of July 28, traveling across the sky beside each other while appearing to be separated by only five degrees, equal to the width of three middle fingers held at arm’s length. (See our favorite photos of the blood moon eclipse from around the world.)

On the 27th, the red planet will reach opposition and be just a few days shy of