I am quite familiar with this star cluster, as some of my research into white dwarfs has been centered on this star cluster. The cluster is young, as far as star clusters go, being "only" 150 million years old. The brightest stars in this cluster are about five times more massive than the sun. Of course, the very bright, orange object in the APOD is the planet Mars, which wasn't there when I took my image above.
I apologize if my picture above looks a little green around the gills. On some computers the sky looks greenish; on others it is black. The green color, if you see it, is just an artifact of how I made the color picture.