The sky is divided into 88 constellations. Astronomers use them as a convenient way to locate and name celestial objects. The boundary of each constellation forms an irregular polygon. People of the ancient Middle East believed that when they connected the brightest stars of a constellation they could see patterns which formed images of fabled creatures. These gave the names to the original 12 constellations of the Zodiac. On the Display menu, click Filter box (or press CTRL+D) to open the Filters dialog box and click the Constellations tab on the left side of the Filter dialog box. You can also open the filter from a pop-up menu located in the header of the Settings panel: click the Filters button in the Settings panel header, then choose constellations from the pop-up menu.