June Tonight’s Sky June Tonight’s Sky Constellations The balmy nights of June are short, but filled with fine sights for the backyard stargazer. Look for the Big Dipper riding high in the northwest. Its handle points toward Arcturus: the fourth-brightest star in the night sky. Arcturus is part of the contellation Boötes, the herdsman. Boötes also contains a double star called Epsilon Boötis, or Izar. The striking pair of stars appears yellow-orange and bluish in a modest telescope. To the left of Boötes sits a semicircle of stars known as Corona Borealis, the Northern Crown. Next to Corona Borealis, we find the dim constellation of a bright hero: Hercules, the strongman of Greek myth. Near the center of the constellation is a trapezoid known as the Keystone. The Keystone is essential to finding the Great Star Cluster in Hercules, a globular star cluster containing hundreds of thousands of densely packed stars. Globular star clusters contain among the oldest stars in our galaxy. All of the stars within a globular cluster formed around the same time. With NASA’s Hubble Space Telescope, we can observe these old stars individually and compare how stars of different masses change as they age. Just outside the Keystone sits another globular cluster: M92. M92 is more distant than the Hercules Cluster, and looks smaller and fainter through a telescope. An image from Hubble shows many bright, old red giant stars in its crowded core. North of Hercules, breathing fire on his feet, lies Draco the dragon. Draco’s long body curls around the Little Dipper. Located along the dragon’s coils is NGC 6543—the Cat’s Eye Nebula, a cloud of expanding, glowing gas from a dying star. - 1 - NASA’s Hubble and Chandra space telescopes bring the Cat’s Eye into detailed view. Red and purple represent visible light emitted by shells of hot gas thrown off by the star. The blue is X-ray emission from hot gas surrounding the white dwarf star that remains at its core. You don’t need cat’s eyes to find the treasures of the June sky—just a dark night, your own eyes, and binoculars or a small telescope to enhance the view. Celestial wonders await you in tonight’s sky. - 2 - .