Tonight's Sky: April

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with NASA’s Universe of Learning partners: Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, NASA Jet Propulsion Laboratory, and Sonoma State University

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 Text, April. Tonight's Sky. Constellations. Stylized drawings of a lion, a ram, and a bull. 

North, 10:30 PM. Looking up into a night sky filled with stars. Text, Clear April nights are filled with starry creatures. Northeast sky. 

A constellation shaped like an upside-down bear with a long tail, four legs, a body and a head. Text, Face north and you will find Ursa Major, the Great Bear. A drawing of a bear appears over the constellation. Text, The Big Dipper, which forms part of the bear, is one of the most familiar star patterns in the sky. The hindquarters and tail of the bear form a square ladle with a long handle. Text, In the middle of the handle lie Mizar and Alcor, a double star discernible with the naked eye. Ground-based view. An image of a large bright white star and a smaller star next to it. Text, A telescope shows Mizar and Alcor as a diamond-white pair of stars. In fact, this is a six-star system. Alcor itself is a binary while Mizar is actually two sets of binaries, a quadruple star. 

During the spring, our view is away from the cloudy plane of the Milky Way and the clear view reveals other galaxies. Near the end of the Big Dipper's handle lies the Pinwheel Galaxy, also known as M101. 

Image of a bright white galaxy with cloud arms spiraling out from a central point. Text, a ground-based telescope reveals its spiral shape. Zoom in on the galaxy, a glowing yellowish center with white-and-tan, cloudy arms spiraling out. Trails of dark dust and bright stars scatter across the spiral. Text, With the eye of the Hubble Space Telescope we can see individual stars that make up this galaxy. The Pinwheel Galaxy is similar in both size and shape to our own Milky Way galaxy. A different view of the galaxy glowing with purple and orange light with blue stars. Text, This composite image shows infrared and X-ray, as well as visible wavelengths of light. Hubble, Spitzer, and Chandra space telescopes. X-ray and infrared light allows us to see the galactic gas that is otherwise invisible to human eyes. Bright X-ray points mark black holes and neutron stars emitting energy as they consume nearby companions. 

Beyond the Big Dipper's bowl lies a pair of galaxies, M81 and M82. Ground-based view, two flat disk-shaped galaxies. Text, the two galaxies are relatively nearby, just 12 million light-years away, and very close to each other, just 150,000 light-years apart. 

Moving across the sky to a constellation forming an irregular rectangular body, triangular tail, and an arching line for a head. Text, South of the Great Bear roams another great beast, Leo the Lion. A drawing of a snarling lion appears over the constellation. Text, Leo's bright heart is marked by the star Regulus, a system of four stars, two double stars circling each other. Within Leo's stomach lie a number of galaxies. Two of them, M95 and M96, are large spirals. 

Zoom in on the galaxy. A bright-white center point surrounded by spiraling red clouds of dust. Text, An infrared view of M95 shows an orderly galaxy seen face on. Infrared light. M96, a slanted spiral of brown and pale dust around a bright central point. Text, A visible light view of M96 shows an asymmetric galaxy, probably gravitationally disrupted by encounters with its neighbors. 

Look skyward for the glittering galaxies and fierce beasts of April. Celestial wonders await you in Tonight's Sky.