http://www.freerepublic.com/tag/apod-chat/ en-us Thu, 31 Dec 2009 16:18:10 GMT Focus Forum 15 http://www.freerepublic.com/focus/f-chat/2418395/posts Dust and the Helix Nebula NASA, JPL-Caltech, Kate Su (Steward Obs, U. Arizona) et al. Explanation: Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image shows infrared radiation from the well-studied Helix Nebula (NGC 7293) a mere 700 light-years away in the constellation Aquarius. The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula, representing the final stages in the evolution of a sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly... NASA http://www.freerepublic.com/focus/f-chat/2418395/posts#comment Thu, 31 Dec 2009 16:18:10 GMT http://www.freerepublic.com/focus/f-chat/2417615/posts Spitzer's M101 NASA, JPL-Caltech, K. Gordon (STScI) et al. 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 own Milky Way Galaxy. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Recorded at infrared wavelengths by the Spitzer Space telescope, this 21st century view shows starlight in blue hues while the galaxy's dust clouds are in red. Examining... NASA http://www.freerepublic.com/focus/f-chat/2417615/posts#comment Wed, 30 Dec 2009 14:44:03 GMT http://www.freerepublic.com/focus/f-chat/2416894/posts Rigel and the Witch Head Nebula Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors) 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 the bright star Rigel, to its right, in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from Rigel. Fine dust in the nebula reflects the light. Pictured above, the blue color of the Witch Head Nebula and of the dust surrounding... NASA http://www.freerepublic.com/focus/f-chat/2416894/posts#comment Tue, 29 Dec 2009 13:59:47 GMT http://www.freerepublic.com/focus/f-chat/2416206/posts Barred Spiral Galaxy NGC 6217 Credit: NASA, ESA, and the Hubble SM4 ERO Team 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 spectacular detail in this recently released image taken by the newly repaired Advanced Camera for Surveys on the orbiting Hubble Space Telescope. Visible are dark filamentary dust lanes, young clusters of bright blue stars, red emission nebulas of glowing hydrogen gas, a long bright bar of stars across the center, and... NASA http://www.freerepublic.com/focus/f-chat/2416206/posts#comment Mon, 28 Dec 2009 13:38:36 GMT http://www.freerepublic.com/focus/f-chat/2415711/posts The Cat's Eye Nebula Credit: J. P. Harrington (U. Maryland) & K. J. Borkowski (NCSU) HST, NASA 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, the features seen in the Cat's Eye are so complex that astronomers suspect the bright central object may actually be a binary star system. The term planetary nebula, used to describe this general class of objects, is misleading. Although these objects may appear round... NASA http://www.freerepublic.com/focus/f-chat/2415711/posts#comment Sun, 27 Dec 2009 14:00:13 GMT http://www.freerepublic.com/focus/f-chat/2415270/posts M51 Hubble Remix S. Beckwith (STScI), Hubble Heritage Team, (STScI/AURA), ESA, NASA Additional Processing: Robert Gendler 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 and dust lanes clearly sweep in front of its companion galaxy (right), NGC 5195. Image data from the Hubble's Advanced Camera for Surveys has been reprocessed to produce this alternative portrait of the well-known interacting galaxy pair. The processing has further sharpened details and enhanced color... NASA http://www.freerepublic.com/focus/f-chat/2415270/posts#comment Sat, 26 Dec 2009 13:32:23 GMT http://www.freerepublic.com/focus/f-chat/2415008/posts A Graceful Arc Credit & Copyright: Tony Hallas 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 Mount Lassen at the left and Mount Shasta at the far right, just below the star and dust clouds of the galactic center. Lassen and Shasta are volcanoes in the Cascade Mountain Range of North America, an arc of the volcanic Pacific Ring of Fire. In the dim, snow-capped peaks, planet Earth seems... NASA http://www.freerepublic.com/focus/f-chat/2415008/posts#comment Fri, 25 Dec 2009 17:32:53 GMT http://www.freerepublic.com/focus/f-chat/2414526/posts Gamma Cas and Friends Credit & Copyright: Processing - Noel Carboni, Imaging - Greg Parker, New Forest Observatory 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. A hot, variable, and rapidly rotating star about 600 light-years distant, Gamma Cas also ionizes surrounding interstellar material, including the wispy IC 63 (left) and IC 59 emission and reflection nebulae. The two faint nebulae are physically close to Gamma Cas, separated from the star by only... NASA http://www.freerepublic.com/focus/f-chat/2414526/posts#comment Thu, 24 Dec 2009 16:39:14 GMT http://www.freerepublic.com/focus/f-chat/2413801/posts December Sunrise, Cape Sounion Credit & Copyright: Anthony Ayiomamitis (TWAN) 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 winter in the northern hemisphere and summer in the south, the Sun rose at its southernmost point along the eastern horizon. Earlier this month, looking toward the Aegean Sea from a well-chosen vantage point at Cape Sounion, Greece, it also rose in this dramatic scene. In the foreground lies the twenty-four hundred year... NASA http://www.freerepublic.com/focus/f-chat/2413801/posts#comment Wed, 23 Dec 2009 16:31:26 GMT http://www.freerepublic.com/focus/f-chat/2412168/posts Star Cluster R136 Bursts Out Credit: NASA, ESA, & F. Paresce (INAF-IASF), R. O'Connell (U. Virginia), & the HST WFC3 Science Oversight Committee 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 light by the newly installed Wide Field Camera peering though the recently refurbished Hubble Space Telescope. Gas and dust clouds in 30 Doradus, also known as the Tarantula Nebula, have been sculpted into elongated shapes by powerful winds and ultraviolet radiation from... NASA http://www.freerepublic.com/focus/f-chat/2412168/posts#comment Mon, 21 Dec 2009 13:49:48 GMT http://www.freerepublic.com/focus/f-chat/2411098/posts Aurora Shimmer, Meteor Flash Credit & Copyright: Bjørnar G. Hansen 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 scene. A study in contrasts, it also captures the sudden flash of a fireball meteor from December's excellent Geminid meteor shower. Streaking past familiar stars in the handle of the Big Dipper, the trail points back toward the constellation Gemini, off the top of the view. Both aurora and meteors occur in Earth's upper atmosphere at... NASA http://www.freerepublic.com/focus/f-chat/2411098/posts#comment Sat, 19 Dec 2009 13:51:24 GMT http://www.freerepublic.com/focus/f-chat/2409828/posts Mojave Desert Fireball Credit & Copyright: Wally Pacholka (AstroPics.com, TWAN) 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, California, a more familiar celestial background was momentarily washed out by the meteor's flash. The background includes bright star Sirius at the left, and Aldebaran and the Pleaides star cluster at the right side of the image. The meteor itself blazes through the constellation Orion. Its greenish trail begins just left of a yellow-tinted Betelgeuse and points back... NASA http://www.freerepublic.com/focus/f-chat/2409828/posts#comment Thu, 17 Dec 2009 20:07:45 GMT http://www.freerepublic.com/focus/f-chat/2408951/posts Comet Hyakutake Passes the Earth Credit & Copyright: Doug Zubenel (TWAN) 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 March. At that time, Comet Hyakutake, dubbed the Great Comet of 1996, became the brightest comet to grace the skies of Earth in 20 years. During its previous visit, Comet Hyakutake may well have been seen by the stone age Magdalenian culture, who 17,000 years ago were possibly among the first humans to live... NASA http://www.freerepublic.com/focus/f-chat/2408951/posts#comment Wed, 16 Dec 2009 19:47:08 GMT http://www.freerepublic.com/focus/f-chat/2407114/posts Saturns Hexagon Comes to Light Cassini Imaging Team, SSI, JPL, ESA, NASA 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 discovered during the Voyager flybys of Saturn in the 1980s, nobody has ever seen anything like it elsewhere in the Solar System. Although its infrared glow was visible previously to the Cassini spacecraft now orbiting Saturn, over the past year the mysterious hexagonal vortex became fully illuminated by sunlight... NASA http://www.freerepublic.com/focus/f-chat/2407114/posts#comment Mon, 14 Dec 2009 13:55:52 GMT http://www.freerepublic.com/focus/f-chat/2406541/posts Crescent Neptune and Triton Credit: Voyager 2, NASA 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 was taken from behind just after closest approach. It could not have been taken from Earth because Neptune never shows a crescent phase to sunward Earth. The unusual vantage point also robs Neptune of its familiar blue hue, as sunlight seen from here is scattered forward, and so is reddened like the setting Sun. Neptune is... NASA http://www.freerepublic.com/focus/f-chat/2406541/posts#comment Sun, 13 Dec 2009 13:42:15 GMT http://www.freerepublic.com/focus/f-chat/2406052/posts Geminid Meteor over Monument Valley Credit & Copyright: Wally Pacholka (AstroPics.com, TWAN) 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 December 14th, around 0510 UT (12:10am EST). With better viewing for northern hemisphere observers, pictures of Geminids streaking through the night could include wintery landscapes, like this snow-tinged image of a 2007 Geminid meteor over buttes of the Monument Valley region in the southwestern US. The meteor streak points back to the... NASA http://www.freerepublic.com/focus/f-chat/2406052/posts#comment Sat, 12 Dec 2009 13:46:04 GMT http://www.freerepublic.com/focus/f-chat/2404576/posts The Colors of IC 1795 Credit & Copyright: Don Goldman 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 palette for mapping narrow emission from oxygen, hydrogen, and sulfur atoms to blue, green and red colors, and further blending the data with images of the region recorded through broadband filters. Not far on the sky from the famous Double Star Cluster in Perseus, IC 1795 is itself located next to IC 1805, the Heart... NASA http://www.freerepublic.com/focus/f-chat/2404576/posts#comment Thu, 10 Dec 2009 15:05:39 GMT http://www.freerepublic.com/focus/f-chat/2403728/posts HUDF Infrared: Dawn of the Galaxies Credit: NASA, ESA, G. Illingworth (UCO/Lick & UCSC), R. Bouwens (UCO/Lick & Leiden U.), & the HUDF09 Team 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 taken this summer by the newly installed Wide Field Camera 3 on the refurbished Hubble Space Telescope. Faint red smudges identified on the above image likely surpass redshift 8 in distance. These galaxies therefore likely existed when... NASA http://www.freerepublic.com/focus/f-chat/2403728/posts#comment Wed, 9 Dec 2009 15:44:41 GMT http://www.freerepublic.com/focus/f-chat/2401970/posts The International Space Station Over the Horizon Credit: STS-129 Crew, Expedition 21 Crew, NASA 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 space station, they took the above image. Visible on the ISS are numerous modules, trusses, and long wing-like solar panels. The space shuttle crew spent almost 12 days calling the space station home. The shuttle crew resupplied the space station and delivered valuable spare parts. The ISS continues to be home for... NASA http://www.freerepublic.com/focus/f-chat/2401970/posts#comment Mon, 7 Dec 2009 13:48:40 GMT http://www.freerepublic.com/focus/f-chat/2401450/posts The Magnificent Tail of Comet McNaught Credit & Copyright: Robert H. McNaught Explanation: Comet McNaught, the Great Comet of 2007, was the brightest comet of the last 40 years. Its spectacular tail spread across the sky and was breathtaking to behold from dark locations for many Southern Hemisphere observers. The head of the comet remained quite bright and was easily visible to even city observers without any optical aide. Part of the spectacular tail was visible just above the horizon after sunset for many northern observers as well. Comet C/2006 P1 (McNaught), which reached an estimated peak brightness of... NASA http://www.freerepublic.com/focus/f-chat/2401450/posts#comment Sun, 6 Dec 2009 13:15:44 GMT http://www.freerepublic.com/focus/f-chat/2400902/posts Himalayan Skyscape Credit & Copyright: Babak Tafreshi (TWAN) Explanation: Capella, alpha star of the constellation Auriga, rises over Mt. Everest in this panoramic view of the top of the world at night. The scene was recorded in late November near Namche Bazar, Nepal, gateway to the Himalayan mountain range. Moonlight illuminates the famous peaks of Everest (8840 meters) and Lhotse (8516 meters) at the far left, and a stupa (a Buddhist religious monument) in the foreground, along the main trail to the Everest Base Camp. The light in the valley is from the Tengboche Monastery, also along the trail... NASA http://www.freerepublic.com/focus/f-chat/2400902/posts#comment Sat, 5 Dec 2009 13:28:51 GMT http://www.freerepublic.com/focus/f-chat/2399420/posts Polar Ring Galaxy NGC 660 Credit & Copyright: Immo Gerber and Dietmar Hager (TAO) Explanation: NGC 660 lies near the center of this intriguing field of galaxies swimming within the boundaries of the constellation Pisces. Over 20 million light-years away, its peculiar appearance marks it as a polar ring galaxy. A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of a flat galactic disk. The bizarre configuration could have been caused by the chance capture of material from a passing galaxy by the disk... NASA http://www.freerepublic.com/focus/f-chat/2399420/posts#comment Thu, 3 Dec 2009 16:38:29 GMT http://www.freerepublic.com/focus/f-chat/2398388/posts Dust Sculptures in the Rosette Nebula Credit & Copyright: John Ebersole Explanation: What creates the cosmic dust sculptures in the Rosette Nebula? Noted for the common beauty of its overall shape, parts of the Rosette Nebula, also known as NGC 2237, show beauty even when viewed up close. Visible above are globules of dark dust and gas that are slowly being eroded away by the energetic light and winds by nearby massive stars. Left alone long enough, the molecular-cloud globules would likely form stars and planets. The above image was taken in very specific colors of Sulfur (shaded red),... NASA http://www.freerepublic.com/focus/f-chat/2398388/posts#comment Wed, 2 Dec 2009 14:07:03 GMT http://www.freerepublic.com/focus/f-chat/2397556/posts NGC 6992: Filaments of the Veil Nebula Credit & Copyright: Daniel Lopez (Observatorio del Teide) Explanation: Wisps like this are all that remain visible of a Milky Way star. About 7,500 years ago that star exploded in a supernova leaving the Veil Nebula, also known as the Cygnus Loop. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant has faded and is now visible only through a small telescope directed toward the constellation of the Swan... NASA http://www.freerepublic.com/focus/f-chat/2397556/posts#comment Tue, 1 Dec 2009 14:05:05 GMT http://www.freerepublic.com/focus/f-chat/2396785/posts Bright Sun and Crescent Earth from the Space Station Credit: STS-129 Crew, NASA Explanation: This was just one more breathtaking view from the International Space Station. The Sun, a crescent Earth, and the long arm of a solar panel were all visible outside a window when the Space Shuttle Atlantis visited the orbiting outpost last week. Reflections from the window and hexagonal lens flares from the camera are superposed. The space shuttle landed Friday after a successful 10 day mission to expand and resupply the ISS. Numbered STS-129, the space shuttle mission returned astronaut Nicole Stott to Earth from... NASA http://www.freerepublic.com/focus/f-chat/2396785/posts#comment Mon, 30 Nov 2009 13:02:36 GMT