Starship Asterisk*

http://apod.nasa.gov/apod/calendar/S_091230.jpg Spitzer's M101 Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our ...

http://apod.nasa.gov/apod/calendar/S_091229.jpg Rigel and the Witch Head Nebula Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula on the lower left is associated with ...

http://apod.nasa.gov/apod/calendar/S_091228.jpg Barred Spiral Galaxy NGC 6217 Explanation: Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a modest central bar . Prominently barred spiral galaxy NGC 6217, pictured above , was captured in spectac...

http://apod.nasa.gov/apod/calendar/S_091227.jpg The Cats Eye Nebula Explanation: Three thousand light-years away, a dying star throws off shells of glowing gas. This image from the Hubble Space Telescope reveals the Cat's Eye Nebula to be one of the most complex planetary nebulae known. In fact , t...

http://apod.nasa.gov/apod/calendar/S_091226.jpg M51 Hubble Remix Explanation: The 51st entry in Charles Messier's famous catalog is perhaps the original spiral nebula - a large galaxy with a well defined spiral structure also cataloged as NGC 5194. Over 60,000 light-years across, M51's spiral arms ...

http://apod.nasa.gov/apod/calendar/S_091225.jpg A Graceful Arc Explanation: The graceful arc of the Milky Way begins and ends at two mountain peaks in this solemn night sky panorama. Created from a 24 frame mosaic, exposures tracking Earth and sky were made separately, with northern California's Mo...

http://apod.nasa.gov/apod/calendar/S_091224.jpg Gamma Cas and Friends Explanation: Gamma Cassiopeiae shines high in northern autumn evening skies. The brightest spiky star in this rich and colorful Milky Way starfield, bluish Gamma Cas marks the central peak in the W-shaped constellation Cassiopeia...

http://apod.nasa.gov/apod/calendar/S_091223.jpg December Sunrise, Cape Sounion Explanation: The Sun is a moving target . Its annual motion through planet Earth's sky tracks north and south, from solstice to solstice, as the seasons change . On December 21st, the solstice marking the first day of wi...

http://apod.nasa.gov/apod/calendar/S_091222.jpg Planetary Systems Now Forming in Orion Explanation: How do planets form? To help find out, the Hubble Space Telescope was tasked to take a detailed look at one of the more interesting of all astronomical nebulae, the Great Nebula in Orion . The Orion ...

http://apod.nasa.gov/apod/calendar/S_091221.jpg Star Cluster R136 Bursts Out Explanation: In the center of star-forming region 30 Doradus lies a huge cluster of the largest, hottest, most massive stars known. These stars, known collectively as star cluster R136 , were captured above in visible ligh...

http://apod.nasa.gov/apod/calendar/S_091220.jpg Tutulemma: Solar Eclipse Analemma Explanation: If you went outside at exactly the same time every day and took a picture that included the Sun, how would the Sun appear to move? With great planning and effort, such a series of images can be taken. The...

http://apod.nasa.gov/apod/calendar/S_091219.jpg Aurora Shimmer, Meteor Flash Explanation: Northern Lights , or aurora borealis, haunted skies over the island of Kvaløya, near Tromsø Norway on December 13. This 30 second long exposure records their shimmering glow gently lighting the wintery coastal...

http://apod.nasa.gov/apod/calendar/S_091218.jpg Southern Geminids Explanation: At least 34 meteors are included in this composite image as they rain through Australian skies during the annual Geminid Meteor shower . Dust particles strung out along the orbit of extinct comet Phaethon vaporize when t...

http://apod.nasa.gov/apod/calendar/S_091217.jpg Mojave Desert Fireball Explanation: Monstrously bright, this fireball meteor lit up the Mojave Desert sky Monday morning, part of this year's impressive Geminid meteor shower . Seen toward the southwest over rock formations near Victorville, Californi...

http://apod.nasa.gov/apod/calendar/S_091216.jpg Comet Hyakutake Passes the Earth Explanation: In 1996, an unexpectedly bright comet passed by planet Earth. Discovered less than two months before, Comet C/1996 B2 Hyakutake came within only 1/10th of the Earth-Sun distance from the Earth in late Marc...

http://apod.nasa.gov/apod/calendar/S_091215.jpg A Fading Moonset Over Hong Kong Explanation: Do stars appear dimmer when nearer the horizon? Yes -- atmospheric air absorbs and reradiates light, so that the greater the airmass through which one peers, the fainter an object will appear. Pictured abov...

http://apod.nasa.gov/apod/calendar/S_091214.jpg Saturns Hexagon Comes to Light Explanation: Believe it or not, this is the North Pole of Saturn. It is unclear how an unusual hexagonal cloud system that surrounds Saturn's north pole was created, keeps its shape, or how long it will last. Originally ...

http://apod.nasa.gov/apod/calendar/S_091213.jpg Crescent Neptune and Triton Explanation: Gliding silently through the outer Solar System , the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase in 1989. The above picture of the gas giant planet and its cloudy moon wa...

http://apod.nasa.gov/apod/calendar/S_091212.jpg Geminid Meteor over Monument Valley Explanation: The Geminids are expected to put on a good show this year. Created as planet Earth sweeps through dusty debris from extinct comet Phaethon , the annual Geminid meteor shower is predicted to peak on Dece...

http://apod.nasa.gov/apod/calendar/S_091211.jpg Messier Craters in Stereo Explanation: Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier , from his famous 18th century catalog. His name is also given to these two large and remarka...

http://apod.nasa.gov/apod/calendar/S_091210.jpg The Colors of IC 1795 Explanation: This colorful cosmic portrait features glowing gas and dark dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia. The nebula's colors were created by adopting the Hubble false-color ...

http://apod.nasa.gov/apod/calendar/S_091209.jpg HUDF Infrared: Dawn of the Galaxies Explanation: When did galaxies form? To help find out, the deepest near-infrared image of the sky ever has been taken of the same field as the optical-light Hubble Ultra Deep Field (HUDF) in 2004. The new image was ...

http://apod.nasa.gov/apod/calendar/S_091208.jpg Ice Moon Tethys from Saturn Orbiting Cassini Explanation: What processes formed the unusual surface of Saturn's moon Tethys? To help find out, NASA sent the robotic Cassini spacecraft right past the enigmatic ice moon in 2005. Pictured above is one of...

http://apod.nasa.gov/apod/calendar/S_091207.jpg The International Space Station Over the Horizon Explanation: This was home. Just over a week ago, the STS-129 crew of the Space Shuttle Atlantis undocked from the International Space Station (ISS) and returned to Earth. As the shuttle departed the sp...

http://apod.nasa.gov/apod/calendar/S_091204.jpg The Double Cluster Explanation: A lovely starfield in the heroic northern constellation Perseus holds this famous pair of open or galactic star clusters, h and Chi Perseii . Also cataloged as NGC 869 (right) and NGC 884, both clusters are about 7,000 ...